Melanocytic matricoma: two cases of a rare entity in women

Melanocytic matricoma is a rare cutaneous adnexal tumor occurring in humans with only 13 cases reported in the literature. The typical lesion is a circumscribed pigmented nodule on sun‐damaged skin. Most cases have occurred in elderly men. The tumor contains a mixed population of matrical cells, supramatrical cells, shadow or ghost cells, and dendritic melanocytes. We report two cases of melanocytic matricoma in two elderly women with unusual histopathological features such as cystic degeneration and focal granulomatous inflammation, which are considered to be atypical for this entity.     

Six cases of perforating pilomatricoma: Anetodermic changes with expression of matrix metalloproteinases

Perforating pilomatricoma (PP) is a rare clinical variant of pilomatricoma presenting as a crusted or ulcerated nodule. Previous reports have suggested that the tumor cells perforate the epidermis through a process of transepithelial elimination. Here, we report six cases of PP and examine the mechanism of transepithelial elimination in PP. Histologically, the dermis above or around the tumor nest exhibited edema, dilated vascular spaces, sparse collagen bundles and absence of elastic fibers, suggesting anetodermic changes in all cases. Immunohistochemistry demonstrated many CD68-positive macrophages around the tumor nests. Matrix metallopeptidase (MMP)-9 and MMP-12 were expressed in the inflammatory cells and tumor cells, and were also present in the epidermis and fibroblasts in all cases. We speculate that in PP anetodermic change caused by MMP and elastases including MMP-9 and MMP-12 may precede elimination of the tumor.     

A Statistical Study of Calcifying Epithelioma,Focusing on the Sites of Origin

We statistically investigated 396 lesions taken from 355 cases of calcifying epithelioma. The distribution of these lesions did not correlate with the density of the hair follicles, but it was in accord with the distribution of intermediate hairs, such as those in the hair border. This relationship may have etiologic significance.     

Multiple perforating and non perforating pilomatricomas in a patient with Churg–Strauss syndrome and Rubinstein−Taybi syndrome

We report an unusual association of multiple perforating and non-perforating pilomatricomas with Churg-Strauss syndrome, and a dysmorphic syndrome evocative of Rubinstein-Taybi syndrome. These syndromes may be independent, but these rare diseases and genetic abnormalities may be linked together.     

Pilomatricoma can differentiate not only towards hair matrix and hair cortex, but also follicular infundibulum, outer root sheath and hair bulge

Abstract:  Pilomatricoma is believed to differentiate towards the hair matrix and hair cortex. To elucidate the origin of differentiation in pilomatricoma, we studied the expression of epithelial keratin (K) and filaggrin (filament aggregating protein) in pilomatricoma. An immunohistochemical study has been made of 53 cases of pilomatricoma using 10 monospecific anti-keratin antibodies and anti-filaggrin antibody. Basophilic cells, transitional cells and shadow cells did not react with epithelial keratins and filaggrin antibodies as well as hair matrix and hair cortex. Instead, infundibular-type epithelium was positive for K1, K10 and filaggrin. Epithelium showing trichilemmal keratinization was positive for K14 and K16. The hair bulge-like structure was positive for K19. The differentiation of pilomatricoma is diversified, and is heterogeneous in epithelial keratin and filaggrin expression. Our results for keratin and filaggrin expression suggested that pilomatricoma can differentiate not only towards hair matrix and hair cortex, but also follicular infundibulum, outer root sheath and hair bulge.     

Two cases of multiple giant pilomatricoma

Pilomatricoma is a skin appendage tumor manifestating as a firm, solitary lesion of the face and upper extremity. It generally measures 0.5 to 3.0 cm in diameter and is typically found in young people. We report a 29-year-old male and a 13-year-old girl who developed three and two protruding masses, respectively. The size of each tumor was larger than 5 cm. The histologic appearance showed sharply demarcated tumor lobules composed of eosinophilic shadow cells and basaloid cells. We describe two unusual cases of multiple giant pilomatricomas and review the literature, emphasizing the number and size.     

Two cases of pilomatrix carcinoma

We report two cases of pilomatrix carcinoma. Wide surgical excision, radiation, and chemotherapy were required for the first patient. The tumor eventually revealed the characteristics of a carcinoma, both clinically and histopathologically, as it recurred. In the second case, although the tumor exhibited the histology of pilomatricoma in the central part of the lesion, there were numerous outgrowing irregular nests of basaloid tumor cells with cellular atypia and frequent mitoses; these are the characteristic features of the pilomatrix carcinoma in its early stages.