Numerous Ontogenetic Roads to Mantle Cell Lymphoma: Immunogenetic and Immunohistochemical Evidence.

To obtain insight into the ontogeny of mantle cell lymphoma (MCL), we assessed 206 patients from a morphological, immunohistochemical, and immunogenetic perspective. Our series included nodal (n = 151), extranodal (n = 28), and primary splenic (n = 27) MCL cases. Skewing of the immunoglobulin heavy variable (IGHV) gene repertoire was noted, with only four IGHV genes accounting for 46% of cases and approximately 70% of cases (107/154) bearing an imprint of somatic hypermutation (SHM) ranging from minimal to pronounced.

Mediastinal parathyroid carcinoma with tumor implants in a child: a unique occurrence.

A case of mediastinal parathyroid carcinoma is reported in a 10-year-old child. This is the first documented case of this occurrence in the authors' knowledge.

Angiolipoma of the thyroid gland.

This is a report of an angiolipoma of the thyroid gland, an extremely rare entity. A thorough search of the literature revealed only one previously reported example. The patient was a 77-year-old woman with a history of a nodular lesion of the thyroid in the context of a multinodular goiter.

Granular cell tumor of the parotid gland: an exceptionally rare occurrence.

The authors report on a case of a granular cell tumor of the parotid gland, which constitutes an extremely rare neoplasm. The infiltrative growth of the tumor may pose the question of malignancy, especially on frozen section. The objective of this report was to function as a reminder of this entity for every pathologist that deals with a biopsy from a lesion of the parotid gland, and furthermore, to keep the unwary away from a possible diagnostic pitfall.

PEComa: another member of the MiT tumor family?

We report 2 cases of PEComa, one occurring in the colon of an 11-year-old boy and the other in the bone (fibula) of a 92-year-old woman. Both tumors consisted of nests of large epithelioid cells surrounded by a fibrovascular stroma. The nuclei were large and vesicular, with prominent centrally located nucleoli.