Rifki Finci

Solitary fibrous tumour arising from sublingual gland: report of a case

A solitary fibrous tumour is a pleural tumour which may rarely be detected at non-pleural sites. In this report, the case of a solitary fibrous tumour arising from the sublingual salivary gland is described.

A central odontogenic fibroma exhibiting pleomorphic fibroblasts and numerous calcifications

A case of an odontogenic fibroma with unusual histopathological features is described. The tumour exhibited numerous, plump, stellate fibroblasts, similar to those found in the so-called giant cell fibroma. This finding has not been described previously in odontogenic fibromas. This case also exhibited an unusually large number of calcifications. Neither of these features should affect the biological behavior of this lesion.

Oncocytic mucoepidermoid carcinoma of the parotid gland: Report of a case with DNA ploidy analysis and review of the literature

A 44‐year‐old female presented with a painful mass in the left parotid gland. Histologic examination revealed the characteristic picture of oncocytic mucoepidermoid carcinoma (OMEC) composed mainly of sheets of oncocytic cells with uniform nuclei and eosinophilic cytoplasm, focally smaller epidermoid cells surrounding poorly formed glandular spaces, and a few cystic structures lined by well‐differentiated mucous cells with intracytoplasmic mucin. Immunohistochemical staining with antimitochondrial antibody showed granular cytoplasmic positivity in oncocytic cells. The resulting histogram for DNA ploidy analysis was of diploid type. OMEC of the parotid gland is a recently described rare neoplasm. Only six cases have been previously reported in the literature. For an accurate approach in the management of patients, OMEC should be considered in the differential diagnosis of oncocytic lesions of the parotid gland, most of which are benign.

Pericardial rhabdomyomatous spindle cell thymoma with mucinous cystic degeneration

Immunohistochemical evidence for mesothelial origin of paratesticular adenomatoid tumour Sir: Isotalo et al. have commented on our recently published study that provided immunohistochemical evidence of mesothelial cell origin for a series of paratesticular adenomatoid tumours. In their letter Isotalo et al. refer to their own study in which they conclude that, rather than being of mesothelial cell origin, adenomatoid tumours are derived from mesenchymal cells. In this study they describe nests of epithelioid cells peripheral to aggregates of adenomatoid tumour acini. Additionally, in two cases of pseudomyxoma peritonei and two cases of testicular hydrocoele, they observed cytokeratin-positive glandlike structures within the stroma and describe a morphological transition between these epithelioid cells and adjacent stromal cells. They speculate that the epithelioid component of adenomatoid tumours develops from mesenchymal cells through a process of induction by submesothelial cells. We remain unconvinced of the validity of the conclusions Isotalo et al. drew from their data. In our own study and in a follow-up study in which we investigated calretinin expression and growth kinetics in the same series of tumours, we have demonstrated that the immunohistochemical phenotypic pro®le of the epithelioid component of both acinar and solid adenomatoid tumours is identical to that of mesothelial cell proliferations. It is highly unlikely that this would be the case if these cells were not of mesothelial cell origin, but were derived by a metaplastic process from what appear to be reactive ®broblasts. It is signi®cant that in adenomatoid tumours no cells intermediate between stromal and mesothelial (epithelioid) cells are seen. In support of this we have shown calretinin staining to be restricted to the epithelioid component of the tumour and that adjacent stroma shows no evidence of calretinin expression. This suggests that rather than being neoplastic in nature the stromal compartment arises through reactive desmoplasia, and further that the observed peripheral nests are local in®ltration by neoplastic cells. As the reactive lesions investigated by Isotalo et al. have all occurred in close proximity to mesothelial surfaces, we believe that the nests of cytokeratin-containing cells in these lesions are implanted mesothelial cells associated with reactive ®brosis. This phenomenon is frequently seen in pleural in ̄ammation and in this context is clearly not metaplastic in nature. Previous reports have shown adenomatoid tumours to have ultrastructural and immunohistochemical features of mesothelial cells and our two studies have provided additional evidence of this.

Unexpected Nature of a Pelvic Mass in Pregnancy: Castleman's Disease

The obstetrician is rarely confronted with a pregnant patient who presents with a large suspicious pelvic mass. Diagnostic tools are not always of value and laparotomy may be performed for obstetric and histopathologic reasons. In this article we present an interesting case of an unusual pelvic mass in pregnancy secondary to benign lymphoepithelial disease (Castlemans disease). We could not find a case similar to the one reported in the medical literature.

Carcinoid Tumor of Undescended Testis

Carcinoid tumor of the testis is rare and its histogenesis is controversial. We report a case of carcinoid tumor in an undescended testis with electron microscopic evidence of neurosecretory granules.

Endometrial squamous cell carcinoma

Endometrial squamous cell carcinoma is an extremely rare female genital malignancy. Only 26 cases which fulfil the Fluhmann criteria have been reported in the literature. In this report, 2 cases of endometrial squamous cell carcinoma are presented, with a review of related current knowledge.

A Pseudotumour of the Bladder

A case of pseudotumour involving the bladder is presented. The differential diagnostic importance of the lesion is stressed.