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Biomedical subjects

M Michal

Publications and source records attributed to M Michal.

At least 145 records · Page 8Linked to original sources
PubMed1997

Liver cell cytoplasmic inclusions in experimental porphyrias: their demonstration with the ferric ferricyanide reduction reaction.

In the present paper we describe needle-shaped and granular cytoplasmic inclusions in the liver cells of mice and rats with experimental porphyria biochemically resembling human porphyria cutanea tarda. The inclusions were inconspicuous in routine histological slides. The ferric ferricyanide reduction reaction, however, enabled us to demonstrate their shape and location within the hepatic lobule. Needle-shaped inclusions are considered to represent a structure specifically seen in experimental porphyrias resembling porphyria cutanea tarda. These structures are similar to the inclusions seen in human porphyria cutanea tarda.

Animals↗
PubMed1997

Ossifying fibromyxoid tumor of soft parts: a report of 17 cases with emphasis on unusual histological features.

Ossifying fibromyxoid tumor of soft parts is an unusual benign neoplasm, with a tendency for local recurrence. Its typical microscopic appearance is that of a multinodular proliferation of round to spindle shaped cells separated by fibrous bands in which bone formation is often seen. Herein, we present the clinicopathologic features of 17 examples of this tumor with particular emphasis on some unusual histopathologic features that may place pitfalls in the diagnosis of this tumor, including satellite micronodules, mucinous microcysts, absence of myxoid areas, crush artifact, multiple microcalcifications, epidermoid cysts, atypical chondroid differentiation with binucleate lacunar cells, pericytic growth pattern, and malignant change. Awareness of these unusual morphologic features should lead to a search for areas displaying the more typical features of ossifying fibromyxoid tumor to arrive at a correct diagnosis.

Adolescent↗
PubMed1997

Calcifying fibrous pseudotumour of visceral peritoneum.

AIMS: Calcifying fibrous pseudotumour, a recently characterized rare but distinctive lesion, has been reported previously only in soft tissues and in the pleura. We describe four cases of calcifying fibrous pseudotumour which arose in the visceral peritoneum of the small bowel and stomach. METHODS AND RESULTS: In contrast to the calcifying fibrous pseudotumour of soft tissues which generally occurs in children, all four cases in our report occurred in adults. We consider the calcifying fibrous pseudotumour to be a distinctive tissue reaction. CONCLUSIONS: Its characteristic appearance of concentric whorls of lamellated collagen associated with psammoma bodies and other forms of dystrophic calcification is entirely different from all other lesions displaying hyaline collagenous deposits, such as inflammatory pseudotumour, desmoid, hyalinizing granuloma or fibrous plaques of peritoneum.

Adult↗
PubMed1997

Benign epithelial structures on the surface of appendices.

Reported here are five cases of rare and hitherto unreported adenomatoid epithelial structures which occurred under the peritoneal surface of appendix vermiformis. These epithelial structures consisted of mature, small non-branching, cystically dilated adenomatoid spaces lined by one or two layers of flat cells without atypia or mitoses. In two cases these structures underwent focal squamous cell metaplasia. It is hypothesized that these epithelial structures arise from the peritoneum. They should be especially distinguished from metastatic adenocarcinoma.

Adolescent↗
PubMed1997

Benign polymorphous mesenchymal tumor (mesenchymal hamartoma) of soft parts. Report of two cases.

We report two cases of a previously unrecognized neoplasm, each characterized by prominent lobular configuration in the subcutaneous tissue. Within the neoplasms were distinctive garland-shaped structures composed of glial fibrillary acidic protein (GFAP) positive cells with indistinct borders, encased in concentric loops of fine collage fibers. In some areas, the neoplastic cells were distributed in small lacunae. The extracellular space between the collagenous tissue and the cells was filled with copious myxoid matrix. One of the neoplasms also demonstrated areas with spindle cells which resembled leiomyoma. Immunohistochemistry was negative for smooth muscle actin (1A4), muscle actin (HHF35), S-100 protein, desmin, cytokeratin, KP1, and epithelial membrane antigen (EMA.) Currently, both patients are free of recurrence or metastasis 2 and 4 years after primary surgical excision. The neoplasms, which we term benign polymorphous mesenchymal tumor of soft parts (BPMT), should be distinguished from ossifying fibromyxoid tumor of soft parts, extraskeletal mesenchymal chondrosarcoma, neoplasms arising in ectopic breast tissue and mixed tumor of the skin.

Actins↗
PubMed1997

[Myofibroblastic proliferative lesions in the paratesticular area].

Myofibroblastic pseudotumorous proliferations have been recognized at a variety of sites. Six cases of paratesticular myofibroblastic lesions with emphasis on the spectrum of morphologic features were described. The microscopic features changed from abundant cellular spindle cell proliferation resembling nodular (pseudosarcomatous) fasciitis to hypocellular and hyalin fibrovascular lesion with extensive dystrophic calcification. The age of the patients ranged from 14 to 77 years. In four cases sarcoma was suspected histologically. Differential diagnosis and histogenesis of the lesion were discussed.

Adolescent↗
PubMed1997

[Morphologic findings in the tracheal wall after long-term intubation and tracheostomy].

Investigation of tracheal wall in 27 patients showed flat ulcerations of mucosa majority of which was combined with marginal squamous metaplasia of superficial conspicuously proliferating epithelial layer. Squamous metaplasia of mucosal glands (sialometaplasia) was found around ulcerations in 14 cases. Fibroproductive inflammatory lesion of tracheal wall was accompanied by a serious destruction of cartilages reminding of that in relapsing chondritis. Regeneration of cartilages was found in 23 cases.

Adult↗
PubMed1997

[Psammomatous melanotic schwannoma].

Psammomatous melanotic schwannoma is a rare variant of schwannoma. The authors present histological and immunohistochemical findings in two cases of the tumor arising in the spinal nerve roots region at a 56-year-old woman and a 58-year-old man. The latter recurred locally. Microscopically the tumor was composed of polygonal epithelioid or spindle-shaped cells. Some of these cells contained melanin. Small calcifications were dispersed throughout the lesion. Ultrastructural examination of one of these cases revealed nerve sheath origin of the tumor cells and identified premelanosomes and melanosomes within the cytoplasm of neoplastic cells. Histogenesis and relationship of the tumor to Carney complex are discussed.

Female↗
PubMed1997

[Simultaneous occurrence of 2 thyroid gland carcinomas].

The concurrent finding of two thyroid carcinomas is rare. The authors present two patients with the concurrent occurrence of two tumours. In the first case--a 51-year-old man--the authors found a medullary carcinoma in the right lobe and a medullary papillary carcinoma in the left thyroid lobe. The medullary papillary carcinoma metastatized into the mediastinal lymph nodes and into the mediastinal tissues in the area above the tracheal bifurcation. From the morphological and immunohistological aspect in the primary tumour of the left lobe as well as in the mediastinum two different clones of tumour cells were found (the medullary component of the tumour responded positively to antibodies against calcitonin and the papillary component to serum against thyroglobulin. The patient was treated by radiotherapy. The tumour progressed however markedly in its medullary component and the patient died one and a half year after the first symptoms from generalization of the tumour. The second patient, a woman, had an occult papillary carcinoma in the right lobe and in the left lobe a of a medullary papillary carcinoma (follicular variant). This type of tumour also metastatized into a cervical lymph node in the area of the left lobe. The patient was treated by radioiodine. Nine months after bilateral thyroidectomy she has no signs of progression of the tumour.

Adult↗
PubMed1996

Corticomedullary tumors of the adrenal glands. Report of two cases. Association of corticomedullary tumor with spindle cell sarcoma.

We describe two cases of corticomedullary tumors of the adrenal gland. The patients suffered from Cushings syndrome and paroxysmal hypertension. The corticomedullary tumors consisted of benign looking cortical adenoma cells growing on the background of the pheochromocytoma cells. We further present the ultrastructural and immunohistochemical features of these tumors. Focally a spindle cell sarcoma arising from the corticomedullary tumor was found in one case. The spindle cell sarcoma was immunohistochemically negative with antibodies to chromogranin, synaptophysin, cytokeratin and S-100 protein. Ultrastructurally the sarcoma was composed of undifferentiated primitive cells poorly endowed with cytoplasmic organelles. Focal transitions of the pheochromocytoma into the spindle cell sarcoma were seen. It is hypothesized that the spindle cell sarcoma was arising from the pheochromocytoma component of the corticomedullary tumor.

Adrenal Cortex Neoplasms↗
PubMed1996

Spiradenoma associated with apocrine adenoma component.

We present a case of spiradenoma associated with an apocrine adenoma component. The transitions between the spiradenoma and apocrine adenoma components were gradual. It could be observed that the small dark cells seen at the peripheries of the cell nodules of the spiradenoma component were replaced by the peripheral flat myoepithelial cell layer in the apocrine component. Similarly, the large pale cells within the centers of the cell nodules of the spiradenoma component were replaced by the brightly eosinophilic secretory cells with decapitations secretion in the apocrine component of the tumor. The reported case proves that at least some spiradenomas are tumors with distinct apocrine instead of eccrine differentiation.

Adenoma↗
PubMed1996

Carcinoma arising in ectopic hamartomatous thymoma. An ultrastructural study.

We present the ultrastructural features of a case of adenocarcinoma arising in ectopic hamartomatous thymoma in a 31 year old man, in the supraclavicular location. The tumor had a cribriform adenomatous component with a granular cell quality and mimicked a metastatic carcinoma. Ultrastructurally, the spindle cell component revealed clusters of tonofilaments and the tumor cells were attached by well developed desmosomes. The cytoplasm of adenocarcinoma cells contained peculiar cup-shaped bodies derived from the endoplasmic reticulum wrapped around the mitochondria.

Adenocarcinoma↗
PubMed1996

Clear cell malignant myoepithelioma of the salivary glands.

Previous reports of monomorphic clear cell carcinoma of the salivary glands have shown inconsistent results with immunohistochemistry, especially for S-100 protein, and this has led to uncertainty about the nature of these tumours. We believe that much can be explained by considering this group as comprising not one but two separate neoplasms, one epithelial and the other myoepithelial. The former has been described as hyalinizing clear cell carcinoma--it generally occurs in the minor salivary glands, and strongly expresses cytokeratins but not S-100 protein or alpha smooth muscle actin. In contrast, this study presents five primary malignant tumours of the major salivary glands also composed largely of a single population of clear cells, but displaying histological and immunohistochemical features of myoepithelial differentiation, such as the formation of collagenous spherules and expression of S-100 protein and actin. A small number of similar tumours have been reported previously. We, therefore, believe that these neoplasms represent a clear cell variant of malignant myoepithelioma (myoepithelial carcinoma).

Actins↗
PubMed1996

Pitfalls in the diagnosis of ectopic hamartomatous thymoma.

We describe four cases of ectopic hamartomatous thymoma with unusual morphological features. In cases 1 and 2 we found a dysplastic glandular component which was often arranged in a cribriform pattern bridging several glandular spaces. In case 2 we found solid adenocarcinomatous areas with infiltrative edges. Case 3 showed widespread smooth muscle differentiation within the spindle epithelial cell component, the presence of multiple clear cell glands which contained a distinct myoepithelial layer and an overall picture which vaguely resembled a sclerosing adenosis of the breast. Case 4 contained frequent foci of multinucleated giant epithelial cells within the markedly cellular spindle cell component: it also showed multiple, hypocellular, myxoid areas containing eosinophilic cords and pearls of squamous cells, and resembled squamous cell carcinoma with a sarcomatoid spindle cell component. We could not find any evidence of a thymic origin or of thymic differentiation in our four cases or in any other reported cases of ectopic hamartomatous thymoma. We believe that ectopic hamartomatous thymomas manifest salivary gland differentiation.

Adult↗
PubMed1996

Salivary gland anlage tumor. A case with widespread necrosis and large cyst formation.

We describe a case of the salivary gland anlage tumor (congenital pleomorphic adenoma). The tumor arose in the nasopharynx as a pedunculated mass. Microscopically most of the tumor contained large necrotic areas which revealed squamous cell metaplasia resulting in the formation of large cysts. This feature has never been described previously in this tumor and might lead to an erroneous diagnosis.

Adenoma, Pleomorphic↗
PubMed1996

Basal cell carcinoma with collagenous crystalloids.

We describe here a unique feature seen in a case of conventional basal cell carcinoma of the skin. In the central portion of the tumor, clusters of collagenous crystalloids composed of radially arranged needle-shaped fibers were found. Such distinct extracellular matrix deposits may occur in rare cases of pleomorphic adenomas and myoepitheliomas of salivary glands, but to the best of our knowledge, they have never before been described in basal cell carcinoma of the skin.

Basal Cell Carcinoma↗