241/501. Multicentric gastric carcinoids complicating pernicious anemia. Origin from the metaplastic endocrine cell population. We report three cases of multicentric carcinoid tumors of the stomach in patients with long-standing pernicious anemia and severe atrophic gastritis (type A). The tumor nodules arose in nonantral gastric mucosa showing marked intestinal metaplasia. Diffuse endocrine cell hyperplasia was present in both fundus and antrum. Antral G-cell hyperplasia was observed. A widely accepted pathogenesis of this syndrome suggests that the proliferating cell type is the argyrophilic, enterochromaffinlike cell native to the gastric body and fundus. Our findings conflict with this view, in that focal argentaffin staining was also present within tumor cells, as well as immunoreactivity for serotonin and substance p (more characteristic of small-intestinal enterochromaffin or Kulchitsky's cells and small-intestinal carcinoids). Findings in these cases at least suggest an alternative possibility: the tumors may derive from small-intestinal-type metaplastic endocrine cells within the atrophic mucosa, rather than the hypertrophic native endocrine cell population. ( info) |
| We present a case of tubular adenomatous metaplasia (nephrogenic adenoma) arising within a urethral diverticulum in a woman complaining of a vaginal mass with dyspareunia. This lesion, which uncommonly affects the urethra, may clinically manifest as a gynecologic condition and mimic a low-grade adenocarcinoma on pathologic assessment. Criteria for diagnosis and current concepts of pathogenesis are discussed. Our findings, including an immunocytochemical work-up, support the concept of a reactive metaplastic response rather than nephrogenic differentiation. ( info) |
| diverticulum of the female urethra has an incidence of 1.4% to 4.7%. It is generally agreed that the majority of these are acquired lesions. There is, however, evidence that some are of congenital origin. Documented cases of diverticula with colon-type tissue are rare. A case of urethral diverticulum with colonic epithelium and features of Paneth cell metaplasia is presented. Causes, symptoms, diagnostic methods, and treatment are discussed. ( info) |
244/501. Multiple lesions of molluscum contagiosum with metaplastic ossification. A 30-year-old woman, suffering from systemic lupus erythematosus and treated with azathioprine and methyl-prednisolone, developed seven molluscum contagiosum lesions of the upper part of her left calf. Histological examination revealed metaplastic ossification in the upper dermis, in close relation to each molluscum contagiosum lesion. Such an association has not been reported before; its occurrence in this case is discussed. ( info) |
| A leydig cell tumor of testis was discovered during evaluation of infertility in a 36-year-old white man with azoospermia and high plasma estrogen level. Histological examination revealed multiple foci of calcification and massive adipose metaplasia. This is the first time that adipous metaplasia is observed in association with leydig cell tumor of testis. ( info) |
246/501. Spindle cell carcinoma of cornea and conjunctiva with pseudosarcomatous metaplasia. light microscopic, electron microscopic and immunohistochemical findings in 2 patients. We studied the electron microscopic and immunohistochemical findings in two elderly patients with spindle cell carcinoma of the cornea and conjunctiva. By light microscopy, correct diagnosis was made by finding the transition between the pleomorphic spindle shaped tumor cells and the overlying squamous epithelium. Ultrastructural findings indicated that squamous cell origin included tonofilament-associated desmosomes and keratohyaline granules in the tumor cells. Positive immunohistochemical staining with antikeratin antibodies provided further evidence to prove the origin of spindle cell carcinoma. Follow-up of the two patients showed the malignant tumor to be quite aggressive in terms of intraocular invasion in the first patient and local recurrence in the second. ( info) |
247/501. Metastatic metaplastic carcinoma of the breast: diagnosis by bronchial brush cytology. Metaplastic carcinoma of the female breast is an uncommon lesion that may metastasize to body sites. To our knowledge, this is the first reported case of pulmonary metastasis diagnosed on bronchial brush cytology. The patient presented with pulmonary symptomatology 1 yr and 3 mo after a left modified radical mastectomy for breast carcinoma. Bronchoscopic examination revealed an endobronchial lesion partially obstructing the bronchus intermedius. Bronchial brush cytology showed the presence of nonkeratinizing squamous tumor cells admixed with a few scattered clusters of tumor cells with glandular features. Histologic review of the original breast lesion showed a metaplastic carcinoma of the breast with a predominant squamous-cell component. Accurate knowledge of a patient's clinical history is necessary to differentiate a second primary lesion from a metastatic one, particularly when the original lesion is so uncommon. ( info) |
248/501. Histopathology of rare chondroosteoblastic metaplasia in benign lipomas. Lipomas are frequent findings in the routine work of a pathologist. Variants of lipomas are characterized by an additional component, e.g. capillaries in angiolipomas, but ordinarily their classification does not pose any problem. In contrast to the high incidence of lipomas metaplastic formation of cartilage and bone is only rarely seen. This metaplasia is thought to develop on the basis of myxoid and chondroid change within the lipoma. Mechanical stress, trophic disturbances, the conspicuously frequent contact with periosteum and even still unknown factors may represent the causes for the metaplastic transformations. Four own case reports of chondro- and osteolipomas are described and discussed in view of the gross and microscopic findings. ( info) |
249/501. A case of conjunctival Spitz nevus: review of literature and comparison with cutaneous locations. We report a case of Spitz nevus of the bulbar conjunctiva in a 15-year-old boy. Clinically, the lesion was juxtalimbic, nodular, red, and 6mm in diameter. Only histologic examination provided the diagnosis. Perusal of the literature revealed seven cases of Spitz nevus of the conjunctiva, but for some of them the histology was incompletely described. We compare the clinical and histologic features in cutaneous and conjunctival nevi and stress the similarity between the two. The histologic criteria which permit differentiation of melanomas and Spitz nevi in conjunctival locations are identified. ( info) |
250/501. Metaplastic bone formation in an unusual neural tumour of the oral cavity. This case report describes an unusual variant of a nerve sheath tumour arising in the oral cavity which was partly surrounded by and contained bone. The differential diagnosis is discussed and the formation of bone within neural tumours reviewed. ( info) |