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Biomedical subjects

M Michal

Publications and source records attributed to M Michal.

At least 109 records · Page 6Linked to original sources
PubMed1999

Oncocytic myoepithelioma and pleomorphic adenoma of the salivary glands.

Twenty oncocytic myoepitheliomas (MEs) and pleomorphic adenomas (PAs) were composed of interlacing fascicles of swollen spindle-shaped or/and epithelioid oncocytic myoepithelial cells showing intense finely granular immunoreactivity with anti-mitochondrial antibody. Focal vacuolation of the cytoplasm of oncocytic myoepithelial cells and their gradual transition into sebaceous metaplasia were observed in 3 cases. Another unusual feature found in 5 cases was the presence of slit-like adenomatoid spaces lined with double-layered oncocytic myoepithelium closely resembling Warthin's tumour. The nuclei of oncocytic cells were characterized by enlargement, hyperchromasia and polymorphism, which should not be confused with malignancy. Oncocytic change in myoepithelial cells in MEs and PAs can cause pitfalls in the differential diagnosis of salivary gland tumours. We describe some unusual histological features associated with onococytic metaplasia in benign myoepithelial cell-derived salivary gland tumours, hoping to help to avoid the overdiagnosis of malignancy.

Adenoma, Pleomorphic↗
PubMed1999

Malignancy-simulating change in parotid gland oncocytoma following fine needle aspiration. Report of 3 cases.

We report here there cases of benign parotid gland oncocytoma with pseudomalignant change that mimic acinic cell carcinoma. All patients underwent fine-needle aspiration biopsy of the tumor 62, 725 and 33 days before surgical excision. In histologic sections, there were clusters of pigmented cells with PAS-positive foamy to finely granular cytoplasm similar to those seen in salivary gland acinic cell carcinomas. This report provides another, previously undescribed, example of a diagnostic pitfall that may be observed in histologic tissue specimens removed after FNA of oncocytic tumors.

Adenoma, Oxyphilic↗
PubMed1999

Atypical decubital fibroplasia associated with bizarre parosteal osteochondromatous proliferation (Nora's reaction).

We describe recurring bizarre parosteal osteochondromatous proliferation (Nora's reaction) associated with atypical decubital fibroplasia in the region of the greater trochanter of the femur in a 52-year-old man. We hypothesize that these two recently introduced entities may represent two forms of tissue response to injury (ischemia) inducing proliferative reaction of bone and cartilage in the vicinity of periosteum, and necroses with hyperplastic granulation tissue and myxoid stroma in the subcutaneous tissues.

Bone Neoplasms↗
PubMed1999

Extraneural retiform perineuriomas. A report of four cases.

We present here four cases of extraneural perineurioma (EP), which occurred in 31, 32, 42 and 43 year old women in the left hand, right arm (2 cases) and right axillary regions, respectively. All tumors were well circumscribed, with a thin capsule. They were 2, 2, 1.5 and 1.5 cm in the largest diameter. Microscopically all tumors had a distinctive appearance composed of interconnected cords of cells which ran in a parallel fashion or formed a characteristically looking cellular lattice. These cords were composed of cells with tapered to stellate shaped nuclei having one or two inconspicuous nucleoli. The space between the cells of the lattice was edematous and empty looking, or it was composed of myxoid matrix, or it was filled with characteristically looking globular deposits of collagen extracellular matrix. These globular deposits of collagen extracellular matrix often indented the nuclei, giving them a stellar appearance. Immunohistochemically all tumors reacted positively with antibodies to epithelial membrane antigen. Antibodies to smooth muscle actin, muscle-specific actin, S-100 protein, cytokeratin AE1/AE3, cytokeratin CAM 5.2, and HMB-45 gave uniformly negative immunohistochemical results.

Adult↗
PubMed1999

Cribriform adenocarcinoma of the tongue: a hitherto unrecognized type of adenocarcinoma characteristically occurring in the tongue.

AIMS: We report a review of our institutional and consultation files in order to select cases of hitherto unrecognized type of adenocarcinoma occurring in the tongue. MATERIALS AND RESULTS: Eight cases of a characteristic adenocarcinoma of the tongue resembled solid and follicular variants of the papillary carcinoma of the thyroid. All the tumours were unencapsulated and were divided by fibrous septa into lobules. Major parts of the lesions were composed of areas with solid and microcystic growth patterns. The most striking cytological feature was that the tumour nuclei were pale-staining with a 'ground glass' quality, and they often appeared to overlap. Immunohistochemically, the tumours expressed cytokeratin and S100 protein and, focally, actin; thyroglobulin was negative. Ultrastructurally the cells had clefted nuclei, and the cytoplasm contained a few mitochondria, lysosomes and Golgi apparatus. Many tumour cells had combined features of both myoepithelial and secretory differentiation-well formed microvilli on their apical borders and bundles of microfilaments. At first presentation, all eight patients had metastases in the regional neck lymph nodes, but all are alive 2-6 years after the initial excision and irradiation. CONCLUSION: We describe a distinctive type of adenocarcinoma of the tongue, for which we propose the name cribriform adenocarcinoma of the tongue (CAT). CAT usually presents with metastases in the neck lymph nodes at the time of presentation. We hypothesize that the tumour might arise from the thyroglossal duct anlage.

Adenocarcinoma, Papillary↗
PubMed1999

Metaplastic (infarcted) Warthin's tumour of the parotid gland: a possible consequence of fine needle aspiration biopsy.

AIMS: The metaplastic (or infarcted) variant of Warthin's tumour is characterized by replacement of much of the original oncocytic epithelium by metaplastic squamous cells, along with areas of extensive necrosis, fibrosis and inflammatory change. The pathogenesis is unknown, but it is most likely to be vascular in origin. An association with a previous fine needle aspiration (FNA) has been suggested, and this is explored further. METHODS AND RESULTS: Nine metaplastic Warthin's tumours were collected from several centres: all arose in the parotid gland, and all showed the characteristic histological features. Eight had previously undergone FNA some 1-4 months before surgery; the other case had had an incisional biopsy. CONCLUSIONS: It is important to recognize metaplastic Warthin's tumour, because the differential diagnoses of this benign neoplasm include mucoepidermoid and squamous carcinoma, both primary and metastatic. The tumours in this study followed FNA or biopsy, and we believe this association is unlikely to be coincidental. Although many metaplastic Warthin's tumours clearly arise spontaneously, we conclude that the balance of probabilities favours the view that FNA is capable of causing metaplastic change in a Warthin's tumour, and may have done so in these cases. If so, this previously unusual subtype will become increasingly common, as FNA becomes more widely used (and its value appreciated) in the investigation of patients with a mass in the neck.

Adenolymphoma↗
PubMed1999

Malignant peripheral nerve sheath tumor with perineurial cell differentiation (malignant perineurioma).

A unique case of malignant peripheral nerve sheath tumor (MPNST) with perineurial cell differentiation occurring in a 63-year-old woman in a subcutis of the forearm is described. The tumor contained cellular and myxoid areas. The neoplastic cells were fusiform with distinct cell borders. They were arranged in storiform pattern and in wavy parallel cell cords in the cellular areas. Focally, a pleomorphism and mitotic activity (including atypical mitoses) similar to those of malignant fibrous histiocytoma were seen. The myxoid parts contained haphazardly oriented cells and scarce lipoblast-like multivacuolated cells mimicking a liposarcoma. In the differential diagnosis, myxoid liposarcoma, dermatofibrosarcoma protuberans, malignant fibrous histiocytoma and low-grade fibromyxoid sarcoma were considered. Immunohistochemically, perineurial differentiation was indicated by the diffuse expression of epithelial membrane antigen and focal reactivity for CD34. The tumor was negative with antibodies to S-100 protein, Leu-7, CD68 (KP1), vimentin and cytokeratin AE1/AE3. Ultrastructure of tumor cells revealed features of MPNST. No recurrence occurred in the patient during 2 years follow up.

Antigens, CD34↗
PubMed1999

Spiradenocylindromas of the skin: tumors with morphological features of spiradenoma and cylindroma in the same lesion: report of 12 cases.

Twelve cases of spiradenocylindromas, which revealed features of both spiradenoma and cylindroma in the same tumor mass, are presented. Nine female patients had multiple neoplasms occurring mostly on the scalp, and two female and one male patient had a solitary cutaneous lesion. Three of the female patients with multiple cutaneous tumors had a familial history of similar cutaneous neoplasms. In one of the patient's family, the multiple cutaneous tumors were known to occur in multiple family members in four consecutive generations. One patient with multiple cutaneous lesions was known to have associated multiple kidney cysts as confirmed by computed tomography. Histologically, spiradenocylindromas are composed of intermixed areas that are either of typical spiradenoma in appearance or of typical cylindroma appearance. Apocrine and trichoepitheliomatous differentiation seen in two cases in the present series points to spiradenomas, as well as cylindromas, having complex hair follicle (folliculo-sebaceous apocrine) rather than eccrine differentiation. The presence of lymphoid tissue was a histological feature in the present series, which was prominent in all the spiradenomatous parts of the tumors and which was scanty or practically absent in all the cylindromatous parts. The selective presence of lymphocytes in spiradenoma and an absence in cylindroma suggest that spiradenomas have the unique property of attracting lymphocytes. The malignant tumors arising in three patients in the present series had the morphology of a poorly differentiated epithelioid neoplasm. Three patients died of the disease and the other patients were either free of disease or alive with disease 1-30 years on follow up.

Adenoma↗
PubMed1999

Atypical lipomatous tumors with smooth muscle differentiation: report of two cases.

Two cases of soft-tissue atypical lipomatous tumors with areas of smooth muscle cell differentiation are presented. The patients were a 72-year-old man (Case 1) and a 62-year-old woman (Case 2); their neoplasms were located in the left inguinal region and on the chest, respectively. The adipocytic component in Case 1 contained cells with nuclear atypism and lipoblasts. Case 2 showed only slight nuclear atypism and lacked any lipoblasts. Smooth muscle fascicles were composed of well-differentiated cells with a few mitoses having none or only a slight atypism. They expressed muscle-specific actin and desmin in both cases. No recurrence was recorded during the follow-up time.

Actins↗
PubMed1999

Papillary intralymphatic angioendothelioma (PILA): a report of twelve cases of a distinctive vascular tumor with phenotypic features of lymphatic vessels.

Six childhood vascular tumors were designated as "malignant endovascular papillary angioendothelioma" by Dabska in 1969. Since then, a few reports of similar cases were published, often called "Dabska tumors." Twelve similar cases were identified in review of vascular tumors from the authors' institutions. There were five men and seven women, including seven adults. Patient ages ranged from 8 to 59 years (mean, 30 years). The tumors occurred in the dermis or subcutis of the buttocks or thigh (n = 6), thumb or hand (n = 3), abdomen (n = 2), and heel (n = 1). The tumor sizes ranged from 1 to more than 40 cm (mean, 7.0 cm). The unifying feature of all cases was distinctive intravascular growth of well-differentiated endothelial cells presenting as a matchstick columnar configuration, sometimes with a large production of matrix that was positive for collagen type IV. In half the cases, these intravascular proliferations had an associated actin-positive pericytic proliferation. There was minimal cytologic atypia and rare to absent mitotic activity. Two cases had an adjacent lymphangioma, and two additional cases had clusters of lymphatic vessels adjacent to the tumor. All but two of the cases showed varying degrees of stromal or intraluminal lymphocytes. Occasional epithelioid endothelial cells were seen, but no cases had features typical of epithelioid, spindle cell, or retiform hemangioendothelioma. Tumor cells were positive for vimentin, von Willebrand factor, CD31, and focally for CD34 and were negative for keratins, epithelial membrane antigen, S-100 protein, and desmin. Vascular endothelial cell growth factor receptor type 3, a recently introduced marker for lymphatic endothelia, was positive in all eight cases that were studied, supporting a lymphatic phenotype. Follow-up in 8 of the 12 cases showed no evidence of recurrences, metastases, or residual disease during follow-ups ranging from 1 to 17 years (mean, 9 years). Based on the proliferative borderline features and the lymphatic phenotype, we propose to designate these tumors as papillary intralymphatic angioendothelioma. Additional cases with extensive follow-up should be studied to rule out variants with malignant potential.

Adolescent↗
PubMed1999

[New entities and pitfalls in the diagnosis of soft tissue tumors].

In the presented review the authors described clinicopathological entities which were defined in soft tissue tumour pathology in the last ten years. They briefly discuss some new aspects of already well known soft tissue tumours and present their own diagnostic and published experiences with these lesions.

Humans↗
PubMed1999

[Sarcomatous chromophobe cell renal carcinoma. 2 case reports].

Chromophobe cell renal carcinoma is a relatively rare primary tumour of the kidney. We present two cases of sarcomatoid transformation in this type of renal cell carcinoma. Described transformation in chromophobe renal cell carcinoma has been reported previously only in four publications. We present a very unusual aggressive recurrence of one of our cases and introduce the first case of sarcomatoid carcinoma arising from chromophobe cell renal carcinoma of the kidney with rhabdomyoblastic differentiation.

Adenocarcinoma↗
PubMed1999

[Extraskeletal myxoid chondrosarcoma with neuroendocrine differentiation].

We describe a case of extraskeletal myxoid chondrosarcoma with neuroendocrine differentiation. The tumor occurred in subcutaneous tissue of the right popliteal region in a 50-year-old man. It measured 5 cm in diameter, was well circumscribed, lobular and gelatinous, and lacked any necrosis or hemorrhage. Histologically, the tumor structure was a typical of extraskeletal myxoid chondrosarcoma. The lesion was lobulated and contained small to medium-sized chondroblast-like cells with ovoid hyperchromatic nuclei and without prominent nucleoli. The cells created cords and nests and showed focally a perivascular rosette-like arrangement. A few of the tumor cells were spindle shaped. The myxoid matrix was stained with alcian blue and this reaction was resistant to prior treatment with hyaluronidase. PAS-positive glycogen was found in the cytoplasm of some tumor cells. Immunohistochemically, the tumor cells were diffusely positive for neuron specific enolase, monoclonal synaptophysin and vimentin. Following antibodies gave negative results: desmin, actins, S-100 protein, pancytokeratin, epithelial membrane antigen, chromogranin A, neurofilament protein, myelinic basic protein, glial fibrillary acidic protein. The patient is well four years after the wide excision of tumor and radiotherapy. Neuroendocrine differentiation in extraskeletal myxoid chondrosarcoma was described at first by Chhieng et al. in 1998 (1). Our observation confirms this interesting finding.

Chondrosarcoma↗
PubMed1999

[Renal angiomyolipoma with a clear cell component].

Case report of a 52-year-old woman with angiomyolipoma of the left kidney. The tumor had appearance of a typical angiomyolipoma predominantly composed of spindle cells, some epithelioid cells and few large hyalinized vessels. Adipose tissue was concentrated into small foci. Unusual presence of large cells with a clear fine granular cytoplasm closely resembled cells of the "sugar tumor" of the lung. Epithelioid cells and occasionally spindle cells were HMB45 positive. A minority of cells also coexpressed S100 protein. Clear cells were usually strongly positive for HMB45 too. Our findings supported consideration of a close relation between clear cell ("sugar") tumor of the lung and angiomyolipoma.

Angiomyolipoma↗
PubMed1998

Signet-ring cell aggregates simulating carcinoma in colon and gallbladder mucosa.

We describe three cases of benign signet-ring cell aggregates in the colon associated with pseudomembranous colitis, adenomatous polyp of the colon and ulcerated mucosa of the gallbladder excised for gallstones. In all cases, we found loose, benign signet-ring cell aggregates overlying the ulcerated mucosa surface, simulating signet ring-cell carcinoma. The most important sign of the benign signet-ring cell aggregates is that they are always confined to the surface of the mucosa of the intestine or gallbladder mucosa or crypts of the intestinal epithelium. In no case did we see an invasion of these cells into the lamina propria of the mucosa. In all cases, the benign signet-ring cell aggregates were immunohistochemically positive with antibodies to cytokeratins. The occurrence of benign signet-ring cell aggregates is a rare and very misleading diagnostic pitfall which must be differentiated from signet-ring cell carcinoma of the colon and gallbladder.

Adenomatous Polyps↗
PubMed1998

Benign mixed epithelial and stromal tumor of the kidney.

We describe a distinctive benign tumor of the kidney in a 48-year-old woman, which was composed of well differentiated ducts set in the spindle cell stroma which was muscle actin, smooth muscle actin and desmin positive, and was morphologically similar to the ovarian stroma. No immature appearing epithelial renal or mesenchymal tissue was present in the tumor. Histologically, the tumor differed from the nephrogenic adenofibroma and the rare cases of adult Wilms tumors, mesoblastic nephromas and cystic nephromas.

Adenofibroma↗