Search

Background: Since the first description by Hashimoto et al., there have been only a few case reports of rippled-pattern tricogenic tumor. In addition, there are no reports on detailed immunohistochemical analyses of this rare neoplasm. We describe here an additional case of rippled-pattern trichogenic tumor with a special reference to its immunohistochemical features., Methods: A nodule arising on the occipital area of a 62-year-old Japanese woman was histologically and immunohistochemically investigated., Results: Histopathologically, the lesion contained various-sized lobular nests, which consisted of oval to elliptical shaped basaloid cells without any atypia and were embedded in the collagenous stroma. Some elongated basaloid cells were arranged in a palisading fashion forming parallel rows of epithelial ribbons in a rippled-pattern. Cytokeratin (CK) immunohistochemistry showed constant expressions of CK1/5/ 10/14, CK5/8, CK14 and CK7, and focal expressions of CK17 and CK19 in the basaloid cells, suggesting a keratin phenotypical similarity to the cells in small nodular type trichoblastoma., Conclusions: The present tumor is a variant of trichoblastoma, and considered to be in close association with the outer root sheath and/ or follicular germinative cells.

We report a case of cutaneous adenocarcinoma on the pubic region of a 56-year-old male. The exophytic tumor showed solid, ductal, and glandular patterns with decapitation secretion and mucinous carcinoma-like nests. Despite the exophytic nature of the lesion, an invasive growth pattern into the deep dermis and subcutaneous fat was seen. An additional characteristic of this tumor was the presence of Paget's phenomenon. From these findings, we conclude that this tumor is an apocrine adenocarcinoma having an unusual clinical appearance and unique histopathological features which have some similarities to apocrine carcinoma of the breast and some to syringocystadenoma papilliferum and nipple adenomatosis.

A 76-year-old Japanese male presented with a subcutaneous nodule in the dorsal cubital region of the right arm. The center of the nodule showed typical features of neuroendocrine carcinoma of the skin. The peripheral portion showed epithelial islands of squamoid cells with horn cysts suggestive of benign appendageal tumor with pilar differentiation. The coexistence of two skin neoplasms in the same lesion would suggest that both tumors developed from common pluripotential stem cell.

We report a rare case of mucinous carcinoma of the skin with mammary infiltrating carcinoma-like patterns. An 82-year-old Japanese male had a gourd-shaped tumor on his scalp. Histopathologically, the posterior portion of the tumor showed small lobules of cuboidal tumor cells with no atypia floating in mucinous lakes. In the anterior portion, there were solid lobules, cords, and strands of anaplastic tumor cells infiltrating into the surrounding stroma. Enzyme- and immunohistochemistry and electron microscopy confirmed the eccrine origin of this tumor. It is suggested that mucinous carcinoma of the skin can occur in association with diverse histological patterns, analogous to mucinous carcinoma of the breast.

A case of squamous cell carcinoma (SCC) with regional lymph node metastasis in a 69-year-old Japanese man is reported. The tumor was characterized by the proliferation of peripheral basaloid, inner squamoid, and glycogen-rich cells, the presence of trichilemmal keratinization, and the presence of ladder-like, membrane-coating granules. These findings suggested that this tumor differentiates toward a hair-follicle structure. The most interesting feature of this tumor was the presence of medusa head-like granules in the cytoplasm of the clear squamoid cells adjacent to the keratinized cells. We have been unable to find any other studies of these granules in squamous cell carcinoma.