Rapidly recurring folliculostellate cell tumor of the adenohypophysis with the morphology of a spindle cell oncocytoma: case report with electron microscopic studies.

We report a rapidly recurring folliculostellate cell tumor of the adenohypophysis in a 63-year-old woman. Morphologically the tumor had the typical appearance of a spindle cell oncocytoma of the adenohypophysis. It recurred within 5 months of selective transsphenoidal resection, requiring a second transsphenoidal operation followed by radiation therapy. The spindle cell oncocytoma (SCO) of the adenohypophysis is a relatively recently described entity and a new addition to the fourth edition of the WHO Classification of Tumors of the Central Nervous System. In our case, the ultrastructural features were significantly different from those so far described in SCO, in that tumor cells formed a network of structures indistinguishable from pituitary follicles. In addition, a minority of tumor cells exhibited endocrine differentiation.

Vitiligo-like leucoderma during photochemotherapy for mycosis fungoides.

We describe four patients with mycosis fungoides (MF) in whom depigmentation, and also leucotrichia in one, occurred following the resolution of the eruption during phototherapy (psoralen plus ultraviolet A treatment in three patients, climatotherapy in one). In all cases, the depigmentation was localized to the area of the pre-existing MF lesions. There was no clinically obvious phototoxicity. Biopsy study including S100 staining in all cases, and electron microscopy in one case, demonstrated the total absence of melanocytes, with no evidence of MF. It is suggested that the phototherapy may have activated a cell-mediated immunity leading to destruction of the melanocytes. We recommend that vitiligo-like leucoderma be added to the list of untoward effects of phototherapy in MF.

Mice overexpressing Bcl-2 in their neurons are resistant to myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE).

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by destruction of myelin. Recent studies have indicated that axonal damage is involved in the pathogenesis of the progressive disability of this disease. To study the role of axonal damage in the pathogenesis of MS-like disease induced by myelin oligodendrocyte glycoprotein (MOG), we compared experimental autoimmune encephalomyelitis (EAE) in wild-type (WT) and transgenic mice expressing the human bcl-2 gene exclusively in neurons under the control of the neuron-specific enolase (NSE) promoter. Our study shows that, following EAE induction with pMOG 35-55, the WT mice developed significant clinical manifestations with complete hind-limb paralysis. In contrast, most of the NSE-bcl-2 mice (16/27) were completely resistant, whereas the others showed only mild clinical signs. Histological examination of CNS tissue sections showed multifocal areas of perivascular lymphohistiocytic inflammation with loss of myelin and axons in the WT mice, whereas only focal inflammation and minimal axonal damage were demonstrated in NSE-bcl-2 mice. No difference could be detected in the immune potency as indicated by delayed-type hypersensitivity (DTH) and T-cell proliferative responses to MOG. We also demonstrated that purified synaptosomes from the NSE-bcl-2 mice produce significantly lower level of reactive oxygen species (ROS) following exposure to H2O2 and nitric oxide (NO) than WT mice. In conclusion, we demonstrated that the expression of the antiapoptotic gene, bcl-2, reduces axonal damage and attenuates the severity of MOG-induced EAE. Our results emphasize the importance of developing neuroprotective therapies, in addition to immune-specific approaches, for treatment of MS.

A composite silent corticotroph pituitary adenoma with interspersed adrenocortical cells: case report.

OBJECTIVE AND IMPORTANCE: A case report of an extraordinary sellar pituitary tumor composed of corticotrophs and adrenocortical cells is presented. To our knowledge, this is only the second one reported in the literature. CLINICAL PRESENTATION: An 18-year-old female patient presented with amenorrhea. INTERVENTION: Investigations revealed a sellar mass, which was excised transsphenoidally. Histologically, two cell types could be readily distinguished, i.e., small basophilic cells that were positive for periodic acid Schiff and adrenocorticotropic hormone and large cells with abundant, slightly vacuolated, eosinophilic cytoplasm that were negative for periodic acid Schiff and adrenocorticotropic hormone. The nature of the tumor was revealed by ultrastructural examination, thus highlighting the importance of this technique in the investigation of pituitary adenomas. Immunohistochemistry with a panel of steroidogenic dehydrogenases and hydroxylases was positive in the large cells, confirming these as adrenocortical cells. CONCLUSION: We suggest that the designation "composite silent corticotroph pituitary adenoma with adrenocortical cells" is an appropriate name for this tumor. The explanation for the presence of the two cell types is obscure. Two theories are considered, as were proposed by the authors of the previous case report regarding the same entity, i.e., 1) the possibility of misplaced embryonic adrenocortical cells and 2) the presence of uncommitted stem cells that differentiate into adrenocortical cells.

Concurrent medullary and papillary carcinomas of thyroid with lymph node metastases. A collision phenomenon.

The simultaneous occurrence of two distinct neoplasms derived from different cells of origin is a recognized, albeit rare, entity. In the thyroid, such lesions could consist of medullary carcinoma composed of parafollicular C cells and well-differentiated carcinoma showing follicular epithelial cell differentiation. We report a patient whose thyroid contained calcitonin-immunoreactive medullary carcinoma and thyroglobulin-positive papillary carcinoma, clearly separated from each other. The tumors metastasized to regional lymph nodes, where they formed foci of composite medullary and papillary carcinoma, with each component maintaining a distinct immunophenotypic profile. The composite metastases are best regarded as collision tumors, as each primary neoplasm exhibited only one line of differentiation. Given the high incidence of papillary carcinoma, the occurrence of the two tumors may be a coincidence. Alternatively, a common tumorigenic stimulus triggering neoplastic transformation of both parafollicular C cells and follicular epithelial cells is a plausible explanation for such a phenomenon.

Cutaneous leiomyosarcoma: case reports and review of the literature.

Two patients with leiomyosarcomas are described, both men with lesions located in the upper trunk. Both lesions were present for more than 10 years. The diagnosis was established after excisional biopsy. The diagnostic criteria are a tumor size greater than 2.5 cm in diameter; a mitotic rate of 1 or more per 5 high-power fields in cellular areas; and electron microscopic verification of smooth muscle cells. The literature is reviewed and the clinical presentation of the 2 patients is discussed. Wide excision is the treatment of choice after histological diagnosis.

Hepatic adenomata in type Ia glycogen storage disease.

Liver adenomata are common in young adults and adults with type Ia glycogen storage disease. Complications that may arise in these patients include acute hemorrhage and malignant transformation. With appropriate dietary therapy, they may partially or completely regress. We describe a young woman with type Ia glycogenosis who developed liver adenomata. Because of its persistence and the significant potential of malignant transformation, liver transplantation was performed. This case is discussed in light of a review of the literature on the subject.