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PubMed1994

A hepatic tumor associated with bilateral renal angiomyolipomas: a variant of angiomyolipoma?

Angiomyolipoma is usually derived from the kidney and composed of well developed vessels, smooth muscle and fat tissue. The liver is the only extra-renal site of angiomyolipoma. A peculiar type of hepatic tumor accompanied by bilateral renal angiomyolipomas is reported here. The tumor was mostly composed of large epithelioid cells and a small part of hyalinized large vessels and foam cell infiltration. Mature adipose tissue was absolutely absent. Epithelioid tumor cells arranged in an alveolar pattern had abundant glycogen and some diastase-resistant periodic acid-Schiff granules without obvious crystals. Immunohistochemical studies revealed that the epithelioid cells were positive for melanoma specific antibody (HMB-45), S-100 protein, aromatic L-amino acid decarboxylase and focally alpha-smooth muscle actin. Many melanosome- or premelanosome-like, electron-dense granules were observed in these cells. Thus, these cells were characterized by differentiation to both immature melanocytes and smooth muscle cells. These epithelioid cells were similar to some cells in the renal angiomyolipomas of the same patient. The hepatic tumor was considered to be a result of monotonous proliferation of the epithelioid cells seen in renal angiomyolipoma. Differential diagnosis of this tumor was discussed.

Actins↗

PubMed2001

Malignant epithelioid angiomyolipoma ('sarcoma ex angiomyolipoma') of the kidney: a case report and review of the literature.

Malignant epithelioid angiomyolipoma is a recently described rare tumor of the kidney. Its existence has been questioned, however, on the basis of incomplete evidence of malignant behavior, the absence of an associated classic angiomyolipoma component, or the absence of immunoreactivity for HMB-45 in some cases. We describe a case that was HMB-45-positive and arose in association with a classic angiomyolipoma. The patient was treated with a partial nephrectomy. Three years later, she developed rapidly enlarging liver nodules. A fine-needle aspiration of the liver confirmed the presence of pleomorphic epithelioid cells morphologically and immunohistochemically identical to those comprising the primary renal tumor. After two cycles of treatment with doxorubicin, there was a 50% reduction in the size of the tumors with marked improvement in performance status. We believe this case confirms the existence of a malignant epithelioid angiomyolipoma.

Angiomyolipoma↗

PubMed1988

[A case of renal angiomyolipoma treated by partial nephrectomy--the management of renal angiomyolipoma from the conservative point of view].

A 25-year-old female was admitted for further investigation of the right renal mass, which was noted during evaluation for hepatitis. She had no personal or family history of stigmas of tuberous sclerosis. On physical examination, a movable hard smooth mass of fist size was palpable in the right abdomen. Drip infusion pyelography revealed an elevation of right kidney. Ultrasonography revealed that the abdominal mass had a high amplitude echo area. On CT the mass was heterogeneous with irregular margin and had regions of low attenuation value, suspicious of a tumor with high fat content. An angiogram of the right renal artery revealed a hypervascular tumor showing multiple saccular aneurysms, and absence of arteriovenous shunting. Based on the aforementioned findings, the mass was diagnosed as renal angiomyolipoma. Partial right nephrectomy was performed through an extraperitoneal approach. Pathological diagnosis was a renal angiomyolipoma. Convalescence was uneventful, and the remaining parenchyma of right kidney was working well on drip infusion pyelography three months after operation. The management of renal angiomyolipoma from the conservative point of view is also discussed.

Adult↗

PubMed2006

Angiomyolipoma with epithelial cysts (AMLEC): a distinct cystic variant of angiomyolipoma.

Renal angiomyolipoma (AML) is typically a solid lesion, composed of varying amounts of adipose, vascular, and muscular tissue, lacking an epithelial component. Although it is known that entrapped renal tubules may be observed in AML, presentation as a cystic mass has not been previously reported. We report the clinicopathologic and immunohistochemical features of four cystic renal AML. The lesions were found in 2 male and 2 female patients, ranging in age from 37 to 76 years, none with a history of hormonal therapy. One of the four patients had known tuberous sclerosis, and this patient and 1 other presented with bilateral cystic renal lesions. Grossly, the lesions measured between 1.3 and 4.5 cm in greatest dimension. Histologically, the lesions were each composed of three components: 1) epithelial cysts lined by cuboidal to hobnail cells; 2) a compact subepithelial "cambium-like" layer of cellular, müllerian-like AML stroma with prominent admixed chronic inflammation; and 3) muscle-predominant AML with associated dysmorphic blood vessels exterior to the cellular subepithelial stroma. Immunohistochemically, the stromal components of all four lesions labeled with HMB-45 and Melan-A, most intensely in the cellular subepithelial stroma, whereas smooth muscle actin and desmin demonstrated the opposite pattern, with greatest intensity in the muscle-predominant AML areas. Immunoreactivity for estrogen and progesterone receptors (ER, PR) and CD10 was present in all cases, with strongest and most diffuse staining in the subepithelial AML cells. The cyst lining cells were positive for pancytokeratin and soy bean agglutinin (the latter characteristic of distal nephron epithelium) but did not label for ER, PR, or melanocytic markers. Although these distinctive lesions may be confused with mixed epithelial-stromal tumor, their lack of female predominance or association with hormone therapy, their distinctive dysplastic blood vessels and disorganized exterior muscular layer, along with their immunohistochemical profile, support their classification as AML with epithelial cysts. Whereas the cysts appear to arise primarily from entrapped collecting ducts, the peculiar subepithelial condensation of AML stromal cells, with morphologic and immunohistochemical features suggesting differentiation toward endometrial stroma, may represent epithelial-induced müllerian differentiation not previously reported in AML.

Adult↗

PubMed2005

Multiple hepatic angiomyolipomas with a solitary omental angiomyolipoma.

Angiomyolipoma (AML) is a rare benign tumor that occurs most commonly in the kidney. Lesions in the liver are usually solitary and multiple AMLs of the liver are extremelyrare. Furthermore, extra renal or hepatic AML are rarely found. We report an unusual case of a 34-year-old man with a solitary omental AML and multiple hepatic AMLs. At the age of 23, the patient underwent right nephrectomy and enucleation of a left renal tumor because of bilateral AMLs. At the age of 34, more than 6 lesions in the liver and an enlarged solitary omental AML were discovered. The omental tumor, 50 x 40mm, 49g, was extirpated; it was well-defined and encapsulated a soft elastic mass. Histologically it was an epithelioid AML and positive for the melanogenesis-related marker HMB-45, the same as the earlier right renal tumor. We describe the first case of a solitary omental AML, which had metastasized, and with more than 6 hepatic AMLs.

Adult↗

PubMed2004

Pulmonary angiomyolipoma recurring 26 years after nephrectomy for angiomyolipoma: benign clinical course.

Angiomyolipoma (AML), a benign renal tumor, has various clinical forms, and the nature of AML is not sufficiently understood because of few reports of long-term observation. We report a 57-year-old female without tuberous sclerosis who developed multiple pulmonary AML 26 years after a right nephrectomy for renal AML. A computed tomogram demonstrated multifocal round lesions with lipid-like density throughout both lung fields. An open lung biopsy revealed a histological diagnosis of pulmonary AML. An abdominal computed tomogram was also compatible with splenic AML. She has been in good health for 12 years since the lung biopsy over the 38 years since the nephrectomy. This case suggests that multicentric AML can recur at distant organs even after long-term silence in a patient who has a past history of renal AML.

Angiomyolipoma↗

PubMed2003

[Differences in morphology and immunohistochemistry between hepatic angiomyolipoma and renal angiomyolipoma].

OBJECTIVE: To investigate the clinicopathological and immunohistochemical characteristics of hepatic angiomyolipoma (AML) and renal AML, and to compare the similarities and differences between the two. METHODS: Hematoxylin-eosin staining and SP immunohistochemical staining were performed on the specimens resected during operation of 12 cases of hepatic AML, 2 males and 10 females, aged 41, and 38 renal AML cases, 14 males and 24 females, aged 43. Wilcoxon rank test was made on the proportions of the 3 kinds of myoid cells and fat tissues. RESULTS: All tumors were composed of three basic components: blood vessels, fatty tissue, and myoid cells epithelioid, spindle, or intermediate in shape. Epithelioid cells accounted for more than 50% of the cells in 6 out of the 12 hepatic AML cases often with apparent cellular and nuclear atypia (12/12), and accounted for less than 25% in all renal AML cases. Spindle-shaped cells were scarcely observed in hepatic AML and were common in renal AML. Nuclear atypia was observed in 20 out of the 38 renal AML cases, 18 cases being mild and 1 being moderate. Fat cells accounted for less than 50% in hepatic AML, and more than 50% in renal AML (P = 0.001). Extramedullary hematopoietic tissue was often seen in hepatic AML but never observed in renal AML. Strong positivity of HMB45 and focal positivity of SMA were common in hepatic AML and strong positivity of SMA and sporadic positivity of HMB45 were observed in the renal AML specimens. CONCLUSION: The histological composition of AML is highly variable in the proportion and distribution of the 3 component cells between hepatic AML and renal AML.

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PubMed1996

A histopathologic and immunohistochemical study of small nodules of renal angiomyolipoma: a comparison of small nodules with angiomyolipoma.

Small mesenchymal nodules (SNs) are observed in some cases of renal angiomyolipoma (AML), with or without tuberous sclerosis. They are composed of blood vessels and/or nonvascular smooth muscle cells (SMCs) and/or fat cells. We examined 20 cases of AML, performed detailed histopathologic and immunohistochemical studies of SNs, verified the histologic relationship between SNs and AMLs, and compared the SNs of the tuberous/nontuberous sclerosis groups. Seventy-seven SNs were observed in five cases of AML. The SNs were 0.11 mm to 20.0 mm in diameter. The location of small-sized SNs in the kidney was variable; almost all of the SNs larger than 3.25 mm were in the renal capsule. The small-sized SNs contained mainly epithelioid-type nonvascular SMCs. Blood vessels and fat cells were not observed in the small-sized SNs but appeared gradually in the large-sized SNs. Almost all of the SNs were rounded lesions, and no fusion was observed between the SNs. Nonvascular SMCs of all of the SNs and AMLs were positive for vimentin, alpha-SM actin, and S-100 protein. The SNs less than 1.13 mm in diameter were negative for HMB-45; the nonvascular SMCs of AMLs and of SNs greater than 1.13 mm in diameter were positive for HMB-45. Nonvascular SMCs of SNs and AMLs showed a neurogenic phenotype. The SNs of the nontuberous sclerosis group contained only SMC components, whereas the same-size SNs of the tuberous sclerosis group contained SMCs, fat cells, and blood vessels. The SNs of the nontuberous sclerosis group may not increase in size or may grow slowly. Some of the SNs of patients with tuberous sclerosis grow to become AML. Although the SNs in patients with nontuberous sclerosis do not contain any blood vessels or fat cells, their SMCs show the histologic and immunohistochemical characteristics of AMLs; this indicates that SNs are the "buds" of AML.

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PubMed1992

Crystalloids in angiomyolipoma. 1. A previously unnoticed phenomenon of renal angiomyolipoma occurring at a high frequency.

We present a description of unique crystalloids in renal angiomyolipoma that have not previously been reported. The crystalloids cannot be identified by hematoxylin-and-eosin staining. Detailed observation after diastase treatment followed by PAS staining revealed needle- and rod-like crystalloids, which were clearly seen even by light microscopy, in 11 of 17 patients. Their appearance was characterized by the following phenomena: (a) They appeared mainly in large epithelioid smooth-muscle cells; (b) they appeared at a relatively high frequency at sites where smooth-muscle cells showed diffuse proliferation and where a hemangiopericytic pattern was observed; (c) they were often detected easily even at a site with a sarcomatous appearance; and (d) PAS-positive, diastase-resistant granules were often observed by light microscopy in the vicinity of crystalloids in all 17 patients. Electron-microscopic observation of one patient also revealed characteristic crystalloids. Prior to our study, only one patient had been reported to show crystalloids by electron microscopy, and the crystalloids were interpreted as renin. However, our study used Bowie's staining and immunohistochemistry to prove they were not renin. The nature of the crystalloids still needs to be elucidated. The fact that they closely resemble structures seen in alveolar soft part sarcoma provides one clue to their identification.

Adult↗

PubMed2001

Immunohistochemical study of microphthalmia transcription factor and tyrosinase in angiomyolipoma of the kidney, renal cell carcinoma, and renal and retroperitoneal sarcomas: comparative evaluation with traditional diagnostic markers.

Angiomyolipoma has a unique immunophenotype with co-expression of muscle-specific actin and melanocytic markers such as HMB-45 and Melan-A. The most recently developed melanocytic markers, microphthalmia transcription factor and tyrosinase, have not been studied in the diagnosis of angiomyolipoma. We tested 29 renal angiomyolipomas (21 classic histology, 4 epithelioid variants, 2 lipomatous variants, and 2 leiomyomatous variants) with an immunohistochemical panel, including microphthalmia transcription factor, tyrosinase, HMB-45, Melan-A, and muscle-specific actin. Results were compared with 15 renal cell carcinomas (9 conventional types, 6 with sarcomatoid change), 2 leiomyosarcomas, 5 liposarcomas, and 1 unclassified high-grade sarcoma. Microphthalmia transcription factor expression was seen in 22 of 29 angiomyolipomas, one renal cell carcinoma, and one well-differentiated liposarcoma (that is, 2 of 23 non-angiomyolipomas; sensitivity 75%, specificity 91%). Tyrosinase expression was seen in 4 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 14%, specificity 100%). HMB-45 was positive in 24 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 83%, specificity 100%). Melan-A was expressed by 25 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 86%, specificity 100%). Muscle-specific actin was expressed by 29 of 29 angiomyolipomas and 2 of 23 non-angiomyolipomas (both leiomyosarcomas; sensitivity 100%, specificity 91% [100% excluding leiomyosarcomas]). Microphthalmia transcription factor showed the most widespread staining in angiomyolipoma (50% of cases staining more than half of the tumor cells) followed by Melan-A (24% of cases staining more than 50%). Only three cases showed positivity for all four melanocytic markers, while in one case each only microphthalmia transcription factor and Melan-A were positive. We conclude that microphthalmia transcription factor, but not tyrosinase immunostaining, has a sensitivity and specificity that rivals those of the established markers, HMB-45 and Melan-A, in the diagnosis of angiomyolipoma. Our data supports the use of a panel in difficult cases that includes antibodies to microphthalmia transcription factor, either Melan-A or HMB-45, and muscle-specific actin to provide the best mix of high sensitivity, high specificity, nuclear and cytoplasmic immunolocalization, and widespread staining of cells within a given tumor.

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PubMed2002

Melanoma markers in angiomyolipoma of the liver and kidney: a comparative study.

CONTEXT: Melanoma markers, especially the new microphthalmia transcription factor (mitf), have not been previously compared in hepatic and renal angiomyolipomas. OBJECTIVES: To evaluate expression of the novel melanocytic markers mitf and tyrosinase in angiomyolipomas, and to compare these markers with the established markers HMB-45 and melan-A in both hepatic and renal tumors. DESIGN: Clinical, histopathologic, and immunohistochemical features of 15 hepatic angiomyolipomas were compared with those of 10 renal angiomyolipomas. RESULTS: No significant differences between patients with hepatic angiomyolipomas and renal angiomyolipomas were found with respect to age, gender, race, and tumor size. Hepatic angiomyolipomas exhibited a predominance of the epithelioid smooth muscle cell component, in contrast to their renal counterparts, which were predominantly spindled. The smooth muscle cells expressed HMB-45 in 100% of cases in both groups, melan-A in 14 of 15 hepatic angiomyolipomas and 8 of 9 renal angiomyolipomas, mitf in 5 of 12 hepatic angiomyolipomas versus 6 of 10 renal angiomyolipomas, and tyrosinase in 3 of 12 and 2 of 10 hepatic angiomyolipomas and renal angiomyolipomas, respectively. The extent and intensity of immunostaining with HMB-45 and melan-A were dependent on whether spindled or epithelioid cells predominated; the epithelioid cells showed stronger and more widespread reactivity than the spindled cells. CONCLUSION: We believe that the best immunohistochemical marker for confirming the diagnosis of angiomyolipoma is HMB-45, followed by melan-A. Routine use of mitf and/or tyrosinase is not indicated.

Adult↗

PubMed2000

Frequent estrogen and progesterone receptor immunoreactivity in renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis.

OBJECTIVE: To determine whether renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis (LAM) express estrogen receptor (ER) and progesterone receptor (PR). DESIGN: Retrospective study of archival tissue. PATIENTS: Twelve women with LAM and angiomyolipomas. SETTING: Fox Chase Cancer Center. INTERVENTIONS: ER and PR expression was studied using immunohistochemistry. The hormonal status of the patients at the time of resection of the angiomyolipoma was determined. RESULTS: Ten of the angiomyolipomas had ER immunoreactivity (83%), and all 12 had PR immunoreactivity (100%). The ER and PR positivity was in the smooth muscle component of the angiomyolipomas only. For five women, pulmonary LAM specimens were also available; two were ER positive (40%), and all five were PR positive (100%). All four angiomyolipomas from women receiving progesterone therapy were ER and PR positive. One tumor from a woman receiving tamoxifen was ER negative and strongly PR positive. One woman was pregnant; her tumor was ER and PR positive. CONCLUSIONS: ER and PR expression is frequent in renal angiomyolipoma cells from women with LAM. PR was more consistently present than ER in angiomyolipomas and in LAM. Our data suggest that angiomyolipoma growth could be affected by hormonal factors. If the growth of LAM-associated angiomyolipomas slows during hormonal therapy, there are two potential implications for LAM patients: first, angiomyolipoma size could serve as a measurable indication of response to hormonal therapy; and second, surgical removal of angiomyolipomas might be avoided in some cases.

Adult↗

PubMed2001

Renal angiomyolipoma: further immunophenotypic characterization of an expanding morphologic spectrum.

BACKGROUND: Renal angiomyolipoma is a benign tumor histologically characterized by proliferation of spindle cells, epithelioid cells, and adipocytic cells in concert with many thick-walled blood vessels. To add further diagnostic confusion, an epithelioid cell-predominant variant of renal angiomyolipoma has recently been described. HMB-45 immunoreactivity correlates with ultrastructural striated organelles that closely resemble premelanosomes, although no evidence of melanogenesis has been documented in this tumor. OBJECTIVE: To further characterize the immunophenotypic and ultrastructural profile of renal angiomyolipoma based on phenotypic cell type (epithelioid, spindle, and adipocytic cell). DESIGN: Formalin-fixed, paraffin-embedded tissues from 27 renal angiomyolipomas and 8 renal cell carcinomas were immunostained with monoclonal antibodies to the melanoma-associated antigens HMB-45, HMB-50, NKI/C3 (CD63), and tyrosinase; the smooth muscle-related antigens calponin and muscle-specific actin (HHF-35); S100; and cytokeratin (CK). All renal angiomyolipomas were also immunostained with a polyclonal antibody to renin. Ultrastructural examination was performed on 9 selected cases. RESULTS: All renal angiomyolipomas stained positive for HMB-45, HMB-50, NKI/C3, muscle-specific actin (HHF-35), and calponin. Overall, HMB-45, HMB-50, and NKI/C3 preferentially stained the epithelioid cells. Tyrosinase staining was present in 50% of the renal angiomyolipomas with adequate tissue for staining (12 of 24 cases); positive staining and intensity paralleled HMB-45, HMB-50, and NKI/C3. Muscle-specific actin (HHF-35) and calponin preferentially stained the spindle cells. The adipocytic cells stained positive for both melanoma-associated antigens and smooth muscle antigens. Epithelioid cells, spindle cells, and adipocytic cells were CK, S100, and renin negative. Ultrastructural findings paralleled immunohistochemical staining patterns. Premelanosome-like organelles and electron dense granules were more readily detected in the epithelioid cells within the tumor, whereas ultrastructural characteristics of smooth muscle cells were more easily found in the spindle cells. All renal cell carcinomas stained positive for CK, NKI/C3 staining was variable, and all were negative for HMB-45, HMB-50, smooth muscle actin (HHF-35), and calponin. CONCLUSION: In renal angiomyolipoma, the epithelioid and spindle cells have preferential staining patterns for melanoma-associated antigens versus smooth muscle antigens, respectively. Positivity in renal angiomyolipoma for HMB-50, NKI/C3, and tyrosinase, in addition to HMB-45, provides evidence for the presence of different melanoma-associated gene products. Immunophenotypic overlap of the 3 histologically distinct renal angiomyolipoma cell populations suggests a common cell line, supporting a unitarian concept for renal angiomyolipoma. Ultrastructural characteristics of the 3 renal angiomyolipoma cell phenotypes parallel the immunophenotype, giving further support to a common cell line. Our study lends further credence to the perivascular epithelioid cell concept as proposed by Bonetti and colleagues.

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PubMed1997

Small (< 1.5 cm) angiomyolipomas of the kidney: characterization by the combined use of in-phase and fat-attenuated MR techniques.

The purpose of this study was to evaluate the ability of in-phase spoiled gradient echo combined with chemically selective fat suppression or out-of-phase spoiled gradient echo MR images to characterize small renal masses as angiomyolipomas. Eleven patients with a total of 35 small (< 1.5 cm) angiomyolipomas underwent MR examination at 1.5T. Eight patients had solitary and three patients had multiple angiomyolipomas. One of the patients with multiple angiomyolipomas had tuberous sclerosis and the number of angiomyolipomas were quantified as 20. MR examinations included in-phase spoiled gradient echo (all patients), chemically selective fat suppressed spin echo (six patients), chemically selective fat suppressed spoiled gradient echo (three patients), selective water excitation spoiled gradient echo (one patient) and out-of-phase spoiled gradient echo (seven patients). Angiomyolipomas were minimally (4 lesions) or moderately (31 lesions) high in signal intensity relative to renal cortex on in-phase spoiled gradient echo images. On out-of-phase spoiled gradient echo images, demonstration of signal void fat-water phase cancellation was present in all eight lesions in the seven patients who were imaged with this sequence. Small lesion size rendered the entire angiomyolipoma signal void in seven of these eight lesions due to phase cancellation artifact. Signal void phase cancellation of lesion border or signal void of the entire angiomyolipoma resulted in high lesion conspicuity in all lesions. Mild loss of signal intensity was observed in 7 lesions and moderate loss of signal intensity noted in 25 lesions on chemically selective fat suppressed images. On chemically selective fat-suppressed images, seven lesions were difficult to identify due to limited signal differences between medium intensity cortex and low intensity angiomyolipomas (six lesions in two patients) and moderate breathing artifact (one lesion in one patient). Characterization of small renal masses as angiomyolipomas may be reliably performed using the combination of in-phase and fat-attenuating MR sequences. Consistent image quality and high conspicuity of fat-water phase cancellation interfaces renders out-of-phase imaging a reliable fat attenuating method to demonstrate the presence of fat in small angiomyolipomas. Breath-hold fat-suppressed spoiled gradient echo is also effective; however, this technique demonstrates less signal loss in fatty lesions and is subject to problems with inhomogeneity of fat suppression.

Adult↗

PubMed1998

Angiomyolipoma of kidney.

Angiomyolipoma of the kidney is a clonal neoplasm, apparently part of a family of neoplasms derived from perivascular epithelioid cells. Early angiomyolipomas are small nodules composed of HMB-45-reactive spindle cells in the renal capsule, cortex, or medulla. Most angiomyolipomas are asymptomatic, and they are more common than previously appreciated, approaching 13 per 10,000 adults. They are much more prevalent in patients with tuberous sclerosis, where they often are accompanied by cysts and occasionally by renal cell carcinoma. That they are rarely diagnosed before puberty in patients without tuberous sclerosis, that large ones are more common in women than men, and that they occasionally grow rapidly during pregnancy suggest that hormones may play a role in stimulating the growth of angiomyolipoma. Pathologists should recognize that the presence of multiple angiomyolipomas is, at the least, presumptive evidence for the diagnosis of tuberous sclerosis and include this in their reports. Typical angiomyolipomas are benign but may have alarming properties: nuclear pleomorphism and mitotic activity, extension into the vena cava (21 cases), and spread to regional lymph nodes (39 cases), without malignant progression. The most common serious complication of renal angiomyolipoma is hemorrhage. Epithelioid angiomyolipoma is a recently recognized variant with malignant potential. Angiomyolipoma and lymphangiomyoma are closely related, and tumors with features of both have occurred. Angiomyolipomas have occurred in other organs in association with renal angiomyolipoma.

Adolescent↗

PubMed2006

Renal angiomyolipoma with malignant transformation, simultaneous occurrence with malignity and other complex clinical situations.

Renal angiomyolipoma is a benign kidney tumor, which is characterized by the presence of mature or immature fat tissue, thick-walled blood vessels, and smooth muscles. However, there is a rare possibility of transformation to a malignancy. This transformation could be toward sarcoma. And also angiomyolipoma could be associated with renal adenocarcinoma in the same kidney. The aim of this study is to show the association of angiomyolipoma with complex clinical situations such as malign transformation, simultaneous occurrence with adenocarcinoma, bilateral tumors with tuberous sclerosis or Wunderlich Syndrome. Findings of clinical presentation, pathological evaluation, urography, ultrasonography, and computerized tomography of 19 patients who were diagnosed angiomyolipoma in our clinic during 1994-2003 were examined retrospectively. Our records indicated that radical nephrectomy was performed in three cases of angiomyolipoma in which the differential diagnosis from adenocarcinoma could not be made and in another case of angiomyolipoma, which was associated with adenocarcinoma. Simple nephrectomy was performed in four symptomatic angiomyolipoma cases with tumor size larger than 4 cm and partial nephrectomy in another case. In one case, renal angiomyolipoma was associated with adenocarcinoma in the same kidney. In one case, post-operative recurrence of angiomyolipoma developed 7 months after nephrectomy. This patient was diagnosed low-grade leiomyosarcoma. Angiomyolipoma is regarded as a benign tumor of the kidney; however, it may also show aggressive behaviors and rarely transform to sarcoma. It may also exist in the same kidney along with adenocarcinoma or sarcoma.

Angiomyolipoma↗

PubMed1999

Chromosomal analysis of renal angiomyolipoma by comparative genomic hybridization: evidence for clonal origin.

Angiomyolipoma has long been considered a hamartomatous polyclonal proliferation. However, recent molecular analyses have indicated that these tumors may be clonal neoplasms rather than polyclonal proliferations. We investigated chromosomal imbalances in angiomyolipoma by comparative genomic hybridization. DNA was extracted from archival paraffin-embedded and frozen tissues of 12 angiomyolipomas (10 usual variant, two epithelioid variant). The 10 angiomyolipomas of the usual variant included bilateral tumors from one tuberous sclerosis patient. Fluorescence ratio distributions from tumor hybridizations were compared with those from control hybridizations to detect changes in DNA copy number with high sensitivity and specificity. We identified 20 chromosomal imbalances in seven sporadic angiomyolipomas, including both tumors of the epithelioid variant. The remaining five tumors, including the two angiomyolipomas from a tuberous sclerosis patient, were devoid of chromosomal imbalances. Seventy-five percent of the imbalances were partial or whole chromosomal deletions involving disparate genomic regions, some of which have previously been associated with tumors of adipose tissue and smooth muscle tumors. Four angiomyolipomas of the usual variant showed 5q deletions with a common region of deletion spanning 5q33 to q34. In two tumors, deletion on 5q was the sole abnormality. One epithelioid angiomyolipoma showed 5q gain encompassing the same region in addition to other alterations. We concluded that (1) Chromosomal imbalances are common in renal angiomyolipomas; (2) Presence of clonal genomic alterations lends further support to the neoplastic pathogenesis of these tumors; (3) The 5q33-q34 region may contain a tumor suppressor gene significant in the histogenesis of some renal angiomyolipomas.

Adult↗

PubMed2006

Frequent [corrected] hyperphosphorylation of ribosomal protein S6 [corrected] in lymphangioleiomyomatosis-associated angiomyolipomas.

Lymphangioleiomyomatosis is a progressive lung disease characterized by a diffuse proliferation of pulmonary smooth muscle cells and cystic degeneration. Lymphangioleiomyomatosis can occur either independently of other disease or in association with tuberous sclerosis complex, a tumor-suppressor gene syndrome caused by mutations that inactivate either TSC1 or TSC2. TSC2 mutations and loss of heterozygosity have been identified in sporadic lymphangioleiomyomatosis-associated angiomyolipomas, thus implicating the TSC/Ras homolog-enriched in brain (Rheb)/mammalian target of Rapamycin (mTOR)/p70 S6 kinase signaling pathway in their pathogenesis. This study was undertaken to determine whether the mTOR/p70 S6 kinase signaling pathway is activated in lymphangioleiomyomatosis-associated angiomyolipomas lacking TSC1/TSC2 loss of heterozygosity. Phospho-ribosomal protein S6 (Ser235/236) immunohistochemistry was performed on five lymphangioleiomyomatosis-associated angiomyolipomas, two matched lymphangioleiomyomatosis pulmonary samples, and three sporadic angiomyolipomas. TSC1/TSC2 loss of heterozygosity was previously excluded in these angiomyolipomas. Moderate or strong phospho-ribosomal protein S6 immunoreactivity was found in all lymphangioleiomyomatosis-associated and sporadic angiomyolipomas, suggesting a high incidence of mTOR/p70 S6 kinase signaling pathway activation despite a lack of TSC1/TSC2 loss of heterozygosity. Focally positive phospho-S6 staining was also evident in both lymphangioleiomyomatosis pulmonary samples. We hypothesized that this S6 hyperphosphorylation could reflect mutational activation of Rheb or Rheb-like protein (RhebL1), Ras family members which directly activate mTOR. Mutational analysis performed on DNA from these eight angiomyolipomas plus five additional sporadic angiomyolipomas did not reveal mutations in exons 3 and 4 (homologous sites of Ras activating mutations) of either Rheb or RhebL1. These data suggest that activation of the Rheb/mTOR/p70 S6 kinase pathway is related to the pathogenesis of lymphangioleiomyomatosis-associated and sporadic angiomyolipomas lacking TSC1/TSC2 loss of heterozygosity. This high incidence of mTOR signaling pathway activation suggests that treatment with mTOR inhibitors, such as Rapamycin, may benefit patients with angiomyolipomas independent of the detection of TSC1/TSC2 loss of heterozygosity.

Angiomyolipoma↗