1/3. Melanocytic matricoma: a report of two cases of a new entity.Many reports exist of pigmented adnexal tumors containing dendritic melanocytes such as pigmented basal cell carcinomas and pigmented pilomatricomas. Correspondingly, melanocytes are a known component of the bulbs of anagen follicles. The phenomenon of melanization of adnexal tumors highlights the interrelationship between melanocytes and adnexal epithelium and may represent normal melanocytes colonizing a neoplastic proliferation. We report on two cases of a unique tumor composed of neoplastic matrical cells with a significant component of melanocytes. Both cases presented as pigmented papules in older men (66 and 80 years, forearm and pectoral region, respectively). Histologically, these were well-defined nodular proliferations composed of variably melanized, pleomorphic, and mitotically active matrical and supramatrical cells forming clusters of "shadow cells." Admixed with the epithelial cells were numerous melanized dendritic melanocytes. Shadow cells expressed keratin 13, and a subpopulation of S-100 protein-positive dendritic cells were evident. No recurrence of any type was found after reexcisions 4 months and 2 years later. We propose the name of melanocytic matricoma for these two heretofore unreported cases of a unique neoplasm composed of matrical cells and melanocytes recapitulating epithelial-melanocyte interaction in the follicular anagen bulb. Although their small size, circumscription and clinical course suggest a benign nature, melanocytic matricomas' cytologic atypia disclose the potential for malignant behavior.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
2/3. Papillary endothelial hyperplasia and dilated lymphatic vessels in bullous pilomatricoma.This is a report of papillary endothelial hyperplasia in a 9-year-old girl with a pilomatricoma showing bullous appearance. Histologically, papillary proliferation of endothelial cells was found within dilated lymphatic endothelium-lined vascular channels overlying a pilomatricoma. The endothelial cells covering the papillae were of a lymphatic endothelial cell nature proved by immunohistochemistry and electron microscopy. Abundant fibrous long-spacing collagen was observed in the connective tissue and fibroblasts within papillae.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
3/3. Giant calcifying epithelioma of Malherbe (pilomatrixoma): imaging features.We present a case of giant calcifying epithelioma of Malherbe (pilomatrixoma) in the right upper arm of a 62-year-old man. It measured 18 x 12 x 8 cm in size, making it the largest of all the cases reported previously. CT clearly demonstrated a well-defined, subcutaneous mass with amorphous calcifications. The mass showed intermediate signal intensity on T2*-weighted MR images and slight contrast uptake on contrast-enhanced MR images. Histopathologically, this tumor showed no aggressive or malignant nature. The patient is without evidence of recurrence or metastasis 3 years following the resection.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |