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PubMed2000

Intraosseous salivary tissue: jawbone examples of choristomas, hamartomas, embryonic rests, and inflammatory entrapment: another histogenetic source for intraosseous adenocarcinoma.

PROBLEM: Hundreds of primary salivary neoplasms have been found to be completely enclosed within the marrow spaces of the maxilla and mandible, yet nonneoplastic salivary tissue has never been convincingly identified within marrow, either separately or adjacent to such neoplasms. This situation has forced the acceptance of an inherently awkward odontogenic origin for all intramedullary salivary carcinomas and adenomas. OBJECTIVE: The purpose of this study was to microscopically evaluate a large number of maxillofacial marrow samples for the presence of intramedullary salivary tissue. STUDY DESIGN: We microscopically reviewed 5034 maxillofacial bone samples from the Latvala Inflammatory Bone Registry for evidence of heterotopic salivary inclusions within the marrow tissues. Contributing surgeons were contacted for each identified case of intraosseous salivary tissue to assure that all submitted tissue was removed from within the marrow spaces rather than from overlying soft tissue. RESULTS: Thirteen of 5034 marrow samples (0.3%) contained heterotopic acinic hamartomas, salivary choristomas, embryonic salivary rests, or entrapped surface glands. Four additional hamartomas of the condyle are described. We report also the chance finding of incipient odontogenic epithelial neoplasms (n = 6) and odontogenic epithelial rests (n = 84) within the fatty marrow and outside the periodontal ligament spaces, confirming that not all odontogenic neoplasms are necessarily of periodontal ligament origin. CONCLUSION: The frequency rate for salivary choristomas, hamartomas, embryonic rests, and displaced surface glands within alveolar bone is no less than 2.6 of 1000 biopsied marrow samples. This provides an additional and quite logical histogenetic explanation for the presence of intraosseous salivary neoplasms.

Choristoma↗
PubMed2001

Survey of somatic mutations in tuberous sclerosis complex (TSC) hamartomas suggests different genetic mechanisms for pathogenesis of TSC lesions.

Tuberous sclerosis complex (TSC), an autosomal dominant disease caused by mutations in either TSC1 or TSC2, is characterized by the development of hamartomas in a variety of organs. Concordant with the tumor-suppressor model, loss of heterozygosity (LOH) is known to occur in these hamartomas at loci of both TSC1 and TSC2. LOH has been documented in renal angiomyolipomas (AMLs), but loss of the wild-type allele in cortical tubers appears to be very uncommon. Analysis of second, somatic events in tumors for which the status of both TSC1 and TSC2 is known is essential for exploration of the pathogenesis of TSC-lesion development. We analyzed 24 hamartomas from 10 patients for second-hit mutations, by several methods, including LOH, scanning of all exons of both TSC1 and TSC2, promoter methylation of TSC2, and clonality analysis. Our results document loss of the wild-type allele in six of seven AMLs, without evidence of the inactivation of the second allele in many of the other lesions, including tumors that appear to be clonally derived. Laser-capture microdissection further demonstrated loss of the second allele in all three cellular components of an AML. This study thus provides evidence that, in both TSC1 and TSC2, somatic mutations resulting in the loss of wild-type alleles may not be necessary in some tumor types-and that other mechanisms may contribute to tumorigenesis in this setting.

Clone Cells↗
PubMed1995

Hamartoma of the breast, an underrecognized breast lesion. A clinicopathologic and radiographic study of 25 cases.

This study investigated the clinical, radiographic, and pathologic features of breast hamartoma. The patients ranged in age from 18 to 89 years, with a mean age of 45 years, and a median age of 43 years. Seventy-five percent of the patients were asymptomatic, other than reporting a breast lump. In two patients, the lesions recurred at 7 and 18 months after the initial resection. The clinical diagnoses were fibroadenoma in 10 cases, carcinoma in 5 cases, hamartoma in 4 cases, and phyllodes tumor and lipoma in 2 other cases. Mammograms were available in 12 cases, the majority of which showed a well-defined mass of homogeneous density. Grossly, these lesions were oval to round, well-circumscribed masses, ranging in size from 1 to 7 cm in maximum dimension (mean, 3.9 cm). The microscopic appearance of these tumors corresponded to their gross appearance. Lesions that were grossly firm, rubbery, and white consisted largely of dense fibroconnective tissue with variable amounts of glandular elements with little adipose tissue. Softer, pale, yellow lesions contained more adipose tissue. A consistent and important diagnostic feature was the presence of both lobules and ducts, in contrast to fibroadenoma in which lobules are often absent or rare. The current trend of mammographic breast screening has made us aware that mammary hamartomas are not uncommon. These lesions may go unrecognized by the pathologists because they show all the constituents of normal breast tissue and may be reported as "no pathological diagnosis" or "normal breast tissue," which are inappropriate diagnoses for a lesion that presents as a palpable and a well-circumscribed mass.

Adolescent↗
PubMed1994

Neurofollicular hamartoma. A new histogenetic interpretation.

Neurofollicular hamartoma is a recently described entity characterized histopathologically by fascicles of spindle cells that are haphazardly arranged and laterally delimited by hyperplastic folliculo-sebaceous units. Immunohistochemical studies have shown the presence of a few S-100-positive cells scattered among the spindle cells. We report five cases of this peculiar entity and compare them to two examples of trichodiscomas. Both hamartomas were characterized by proliferations of spindle cells in close association with prominent folliculo-sebaceous units. Based on the clinical and histopathological findings, as well as the immunoperoxidase stains, we conclude that neurofollicular hamartomas are not different from trichodiscomas and fibrofolliculomas.

Adult↗
PubMed1995

Acquired genital smooth-muscle hamartoma. A case report.

Smooth-muscle hamartoma is an uncommon, usually congenital malformation of smooth-muscle origin. When it is acquired, it may be confused with Becker's nevus with a prominent smooth-muscle component. Over the past 3 decades, only two cases of acquired smooth-muscle hamartoma without the concomitant appearance of hairy-pigmented lesions have been reported. We describe a third case. To the best of our knowledge, this is the first case of smooth-muscle hamartoma to occur in the scrotum.

Adult↗
PubMed2003

Familial basaloid follicular hamartoma: lesional characterization and review of the literature.

Basaloid follicular hamartoma (BFH) is a rare cutaneous lesion associated with the acquisition of small papules that remain stable for many years. Basaloid follicular hamartoma lesions can present sporadically or as part of an inherited syndrome. Occasionally, biopsies of BFH lesions are interpreted as basal cell carcinoma (BCC), which necessitates complete removal of the lesion. In this report, we characterize a case of a familial BFH syndrome and discuss the clinical, histologic, and molecular features of BFH lesions that help to distinguish it from BCC. The BFH lesions in our patients remained stable for many years. Histologically, BFH lesions exhibit fewer mitoses and decreased single cell necrosis when compared with BCC. Immunohistochemical staining for the proliferation markers proliferating cell nuclear antigen and Ki-67 demonstrated less staining in BFH than in BCC. In addition, levels of PTCH (patched) mRNA were increased relative to unremarkable epidermis in familial BFH lesions but to a lesser degree and in a different pattern than that seen in BCC. In summary, familial BFH can be distinguished from BCC based on clinical, histologic, and molecular features and is associated with deregulation of the PTCH pathway. Basaloid follicular hamartoma may represent an indolent lesion within the spectrum of basaloid epithelial neoplasms associated with deregulation of the PTCH signaling pathway. We discuss this case in parallel with a growing body of literature that supports the nosologic designation of BFH.

Adult↗
PubMedDate not supplied

Report of changing signal intensity on follow-up MRI in a case of hypothalamic hamartoma.

We present a case of hypothalamic hamartoma in which the signal intensity of the lesion significantly changed during the course of follow-up. To date, stability of the lesion morphology over time has been considered an important diagnostic criterion of hypothalamic hamartoma. Radiologists should be aware that in hypothalamic hamartoma, signal intensity can change during its natural course.

Female↗
PubMed2001

Successful surgical relief of seizures associated with hamartoma of the floor of the fourth ventricle in children: report of two cases.

OBJECTIVE AND IMPORTANCE: To discuss the physiopathology and surgical handling of seizures due to hamartoma of the floor of the fourth ventricle in two children. CLINICAL PRESENTATION: Two girls aged 3 years at the time of their operations presented with seizures due to a lesion of the floor of the fourth ventricle. The seizures began within the first days of life and consisted of hemifacial contraction, then head deviation, blinking of the eyelids, and intermittent dysautonomic manifestations. The interictal neurological condition seemed normal in one patient and showed a slight development delay in the other. An ictal electroencephalogram showed slow waves in the posterior areas. A magnetic resonance imaging scan revealed a mass that remained unchanged on serial examinations bordering the fourth ventricle, with an isointense signal on T1-weighted sequences and high-intensity signals on T2-weighted sequences without gadolinium enhancement. An ictal single-photon emission computed tomographic scan showed hyperperfusion in the lesion in both girls. INTERVENTION: The operation consisted of resection and disconnection of the lesion. An electrical recording was obtained in one patient during the operation while she was anesthetized; the recording, made by means of a depth electrode with five contacts inside the lesion, indicated that repetitive theta rhythmic discharges were present. Neuropathology was consistent with a hamartoma. In both girls, the seizures disappeared after their operations, and antiepileptic drugs were withdrawn (follow-up periods, 8 and 3 yr, respectively). CONCLUSION: Considering the results of single-photon emission computed tomography, the intralesional electrical record, and the relief of seizures after the operation, we postulate that the seizures arose from inside the lesion. This particular kind of noncortical seizure is similar to gelastic seizure due to hypothalamic hamartoma.

Brain Diseases↗
PubMed1992

Familial occurrence of combined pigment epithelial and retinal hamartomas associated with neurofibromatosis 2.

Combined pigment epithelial and retinal hamartomas are rare lesions that usually occur sporadically in individuals without systemic abnormalities. However, they have been reported in isolated patients with neurofibromatosis 1 and 2. No familial cases have been reported. The cases of four patients with unilateral macular lesions from three consecutive generations of a single family are presented: two of the patients also have neurofibromatosis 2. The ophthalmoscopic appearance of their ocular lesions resembles combined pigment epithelial and retinal hamartomas. The morphologic differences in the lesions of these 4 patients, whose ages are 8 months, 5 years, 29 years, and 65 years, may serve to demonstrate the evolution of this type of hamartoma.

Adult↗
PubMedDate not supplied

Hepatic mesenchymal hamartoma in a neonate: a case report and review of the literature.

To describe an unusual presentation of mesenchymal hamartoma in a critically ill neonate necessitating a novel therapeutic embolization before definitive resection. An unusual presentation of a large hepatic mass in a newborn complicated by pulmonary hypertension and vascular "steal" with renal insufficiency is presented. The mass was initially successfully embolized, but then revascularized, necessitating resection in an attempt to improve the clinical status of the critically ill neonate. The resected mass was a mesenchymal hamartoma with a necrotic center and extensive arterial collateralization. The patient began improving immediately after resection. Mesenchymal hamartoma may present in the neonate as a diagnostic dilemma. This is the first case report describing persistent pulmonary hypertension and renal compromise from this tumor. Embolization as a therapeutic modality to address this tumor is described. The cause of the persistent and severe pulmonary hypertension remains unclear,but may be related to the tumor.

Acute Kidney Injury↗
PubMed2006

Formation of the 12q14-q15 amplicon precedes the development of a well-differentiated liposarcoma arising from a nonchondroid pulmonary hamartoma.

Pulmonary hamartoma is a benign neoplasm that rarely recurs or undergoes malignant transformation. Herein, we report a 48-year-old woman with a history of an incomplete excised nonchondroid pulmonary hamartoma presenting as an indolent tumor recurrence. Excision of the tumor revealed a well-differentiated liposarcoma arising from the hamartomatous component. Fluorescence in situ hybridation analysis for HMGA2 and MDM2 was performed on both hamartomatous and liposarcomatous component. MDM2 and HMGA2 amplification were found in a subset of stromal cells in the hamartomatous component and in most cells of the well-differentiated liposarcoma. No rearrangement HMGA2 was found in the pulmonary hamartoma component. These findings suggest that the formation of the 12q14-q15 chromosome amplicon, the characteristic cytogenetic finding of well-differentiated liposarcomas and the structural genomic component of the supernumerary ring and giant rod chromosomes, occurred before the morphologic changes characteristic of these malignant adipose tissue tumors and likely represents a very early molecular event in their development.

Chromosomes, Human, Pair 12↗
PubMed2005

Neuromuscular hamartoma of the occipital nerve: clinical report.

Neuromuscular hamartoma is a rare benign tumor consisted of well-differentiated striated muscle fibers within mature neural elements. Though most cases are composed of solitary masses associated with major peripheral nerves, multiple tumors or subcutaneous tumors without any association with peripheral nerves have also been reported. Twenty-three neuromuscular hamartomas of various anatomical locations have been reported in English literature. There have been no reports of this tumor in association with the occipital nerve. An interesting case of neuromuscular hamartoma of the occipital nerve is presented and previous reports about this rare pathology is reviewed.

Child↗
PubMed2005

Emergency transcallosal resection of hypothalamic hamartoma for "status gelasticus".

Hypothalamic hamartomas are rare developmental malformations of the inferior hypothalamus. Typically they result in symptomatic, refractory mixed seizure disorder with trademark gelastic or laughing seizures. We present a 30-month-old boy with a hypothalamic hamartoma and a nearly 2-month history of near-continuous gelastic seizures, which we have labeled "status gelasticus." The seizures were refractory to multiple antiepileptic drugs (AEDs), and emergency transcallosal resection of the hypothalamic hamartoma was performed with resultant near-immediate cessation of the seizures. At 12-month follow-up, the patient was averaging one brief gelastic seizure every 2 weeks, with a longest seizure-free period of 2 months.

Child, Preschool↗
PubMed2005

Hypothalamic hamartomas and seizures: distinct natural history of isolated and Pallister-Hall syndrome cases.

PURPOSE: Hypothalamic hamartomas (HHs) have been associated with uncontrolled seizures, and aggressive therapy including surgery is often recommended. However, some patients, particularly those with other findings associated with Pallister-Hall syndrome (PHS), have a more benign course. METHODS: Thirty-seven of 40 PHS patients and 16 of 16 patients with isolated HH had a lesion confirmed on magnetic resonance imaging (MRI). Records for all patients were reviewed for the following information: presence of seizures, age at seizure onset, seizure type, seizure frequency, number of antiepileptic medications (AEDs) at the time of evaluation, past AEDs, MRI characteristics of the HH, presence of endocrine dysfunction, and presence of developmental and behavioral problems. RESULTS: All isolated HH patients had a history of seizures, compared with 13 of 40 PHS patients (all PHS patients with seizures had hamartomas). In isolated HH, seizures started earlier in life, occurred more frequently, and were harder to control than those in patients with PHS. Isolated HH patients were more likely to have behavioral and developmental problems than were PHS patients. The T2 signal of the hamartoma was isointense to gray matter in the majority of PHS patients, but showed a significant increase in all but one patient with isolated HH. CONCLUSIONS: Patients with isolated HH have a distinct clinical phenotype, showing more severe seizures and neurologic dysfunction, HH showing increased T2 signal, and are more likely to have precocious puberty. In contrast, PHS patients usually have well-controlled seizures and other endocrine disturbances than precocious puberty. Patients with HH with or without seizures should be evaluated carefully for other clinical manifestations of PHS, particularly before surgery is considered.

Abnormalities, Multiple↗
PubMed1991

A pedunculated follicular hamartoma: a case showing a central trichofolliculoma-like tumor with multiple trichogenic tumors.

We report a rare case with a pedunculated nodule on the nasal septum, which seems a kind of follicular hamartoma with a pedunculated appearance. Our case was a 77-year-old Japanese male with an 11 x 11 x 10 mm sized, skin-to-pink colored, pedunculated nodule on the center of his nasal septum. Histopathological study revealed the nodule to be a well-formed dilated hair follicle at the central pore of the tumor, where keratin debris and vellus hairs were present. In addition, epithelial cells forming long thin strands or immature follicle-like structures had proliferated multifocally from the epidermis of the wall of the central follicle to the peripheral epidermis. One distinctive feature was the formation of a primary germinal bud with thick concentric collagen fibers and sparse elastic fibers. Although a combined tumor of trichofolliculoma with highly-graded desmoplasia, multiple trichogenic trichoblastomas, and perifollicular fibromas was suggested, calling it a pedunculated follicular hamartoma seemed more useful because the pathological features were basically similar to reported follicular hamartomas and the clinical feature was so distinctive.

Aged↗
PubMed1992

Mammary hamartoma--a review of 35 cases.

Mammary hamartomas are macroscopically well-delineated tumours composed of a variable mixture of epithelial elements, fat and fibrous tissue. Such lesions are an under-recognized entity and, as they can be visualized by mammography, may be seen more frequently with the advent of the UK National Breast Screening Programme. The clinical and pathological features of 35 cases of mammary hamartoma seen at the Imperial Cancer Research Fund Clinical Oncology Unit at Guy's Hospital between 1979 and 1990 have been reviewed. Hormone receptor analysis on nine cases gave high progesterone with low oestrogen levels, probably reflecting their premenopausal status. Immunohistochemistry showed that the positive receptor staining was confined to the epithelial elements. In 25 cases pseudo-angiomatous hyperplasia was evident in the stroma of the lesion. The importance of distinguishing the inter-anastomosing stromal spaces seen in the latter condition from low-grade angiosarcoma is emphasized; the relationship between pseudo-angiomatous hyperplasia and mammary hamartoma is discussed; and the possibility that the former represents a permanently dilated form of the lymphatic labyrinth suggested.

Adolescent↗
PubMed2003

Histopathological characteristics of eruption mesenchymal calcified hamartoma: two case reports.

Odontogenic calcified masses were present in the opercula of lower first molars that were delayed in eruption. The masses were relatively small, opaque, white in color with a smooth texture. Histopathological examinations revealed that they contained osteodentin, cementum, and pulp-like components; however, not odontogenic epithelial cells or enameloid. Further, mesenchymal multinucleated giant cells and dysplastic dental matrices were observed in the connective tissues surrounding the masses. These clinical and histopathological findings disagree with the features of pericoronal odontogenic hamartoma lesions, including odontoma, ameloblastic fibroma, and ameloblastic fibro-odontoma. Therefore, we propose to categorize this odontogenic mass as a new variety of hamartoma, eruption mesenchymal calcified hamartoma.

Calcinosis↗
PubMed2005

Basaloid follicular hamartoma.

Basaloid follicular hamartoma (BFH) is a unique benign follicular hamartoma characterized by variable clinical presentations, identical histologic features and possible associations with numerous disorders. Basaloid follicular hamartoma may be hereditary or acquired. Hereditary cases may be either generalized or unilateral nevoid. Although the generalized forms are usually associated with systemic manifestations, such as myasthenia gravis,(2) it may occasionally present without internal disorders. On the other hand, the acquired forms of BFH may present in the form of localized or solitary forms. Herein we present four cases of BFH, one of them (first case) represents a unique form of the generalized variant of BFH, showing no associated internal disorders.

Adolescent↗