1/27. 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. ( info) |
| BACKGROUND: desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, malignant neoplasm that has recently been characterized. It has not been associated with a primary visceral organ. In women, cases are even more rare and often have some ovarian involvement. CASE: An 11-year-old girl presented with abdominal pain, nausea, and vomiting. A CT scan revealed a large heterogeneous pelvic mass with cystic components and an 8-cm midabdominal mass. During exploratory laparotomy, the patient was found to have a pelvic mass measuring 12. 9 cm replacing normal ovarian tissue. The midabdominal mass was also removed. pathology, cytology, and immunohistochemistry confirmed a desmoplastic small round cell tumor. Even with aggressive surgical and medical intervention, the patient died 11 months after initial diagnosis. CONCLUSION: We present a rare small cell tumor that is associated with ovarian involvement. The prognosis in these patients is extremely poor and very few survivals have been reported. ( info) |
3/27. Trichoblastoma of the skin occurring in the breast. A case report. BACKGROUND: Trichoblastoma is a rare benign skin appendage tumor constituted mostly of follicular germinative cells. It can arise on any part of the body except the palms, soles, nail units and mucosal membranes. No case of it in breast skin has been reported before. Furthermore, fine needle aspiration cytology findings on this lesion have not been described before. CASE: A 76-year-old female presented with a firm nodule in her left breast. The tumor was well demarcated, about 1.5 cm in diameter. Fine needle aspiration cytology revealed clusters composed of relatively uniform cells with a high nuclear/cytoplasmic ratio. In the midst of some clusters, the tumor cells had a more abundant cytoplasm. Fibrocellular interstitium or dense cyanophilic acellular material occasionally was attached to them. The tumor cells had oval or fusiform nuclei that had fine, evenly dispersed chromatin. To exclude a diagnosis of breast cancer, it is important to recognize that the clusters are composed of basaloid cells with focal squamous eddies and that there is at least focally peripheral palisading. The histopathologic diagnosis was trichoblastoma. CONCLUSION: Fine needle aspiration cytology can distinguish trichoblastoma from malignant diseases of the breast and may be used to diagnose the lesion in conjunction with clinical findings. ( info) |
4/27. Linear syringocystadenoma papilliferum of the thigh. Syringocystadenoma papilliferum usually arises in the head and neck region. Linear lesions occurring in other locations are rare. We report such a case occurring on the thigh, documented by multiple biopsy specimens. The case is discussed in the context of other adnexal tumors that may form linear arrangements. ( info) |
5/27. Trichilemmal carcinoma in an African American. BACKGROUND: Trichilemmal carcinoma is an uncommon cutaneous neoplasm found primarily on the sun-exposed skin of the elderly. OBJECTIVE: To report a case of trichilemmal carcinoma presenting as a forehead nodule in an African American patient. methods: Case report and review of the literature. RESULTS: Our patient is the first reported case in the English language literature of trichilemmal carcinoma in an African American individual with skin phototype VI. CONCLUSION: The occurrence of trichilemmal carcinoma in our African American patient suggests the diagnosis of trichilemmal carcinoma be added to the differential diagnosis of a nodule on the head region in this patient population. ( info) |
6/27. Trichoblastic neoplasm with apocrine differentiation. Trichoblastoma is a benign neoplasm with primitive hair follicle differentiation. The tumor is characterized by nests and cords of epithelial cells in an organized relation to stroma. The epithelial cells differentiate toward follicular germ and follicular sheath. More divergent differentiation in the form of sebaceous elements in trichoblastoma has infrequently been reported in the literature. We report a trichoblastic neoplasm showing typical features of trichoblastoma as well as areas of apocrine differentiation. The neoplasm, which was present for several months, was removed from the chin of a 31-year-old woman. Histologic examination showed a neoplasm composed of basaloid nests with occasional papillary mesenchymal bodies as well as ducts and glands exhibiting apocrine differentiation. Trichoblastoma with apocrine features is rarely reported in the literature. ( info) |
7/27. Multiple familial trichoepitheliomas: a folliculosebaceous-apocrine genodermatosis. We reviewed the pathologic findings on a family with multiple hereditary trichoepitheliomas. Although the majority of the lesions were trichoepitheliomas, basal cell carcinomas, spiradenomas, and spiradenomas with cylindromatous foci (spiradenocylindroma) were present, representing a spectrum of lesions exhibiting folliculosebaceous (trichoepithelioma, basal cell carcinoma) and apocrine (spiradenoma, spiradenocylindroma) differentiation. Multiple familial trichoepitheliomas may be a syndrome whereby tumors develop from undifferentiated germinative cells of the folliculosebaceous-apocrine unit. Published findings regarding the genetics of this syndrome and solitary trichoepitheliomas are reviewed; although the molecular basis for the tumors has yet to be determined, current data suggest that a tumor suppressor gene may be involved. ( info) |
8/27. Trichogerminoma: a rare cutaneous adnexal tumor with differentiation toward the hair germ epithelium. In 1992, Sau and colleagues described 14 cases of a rare cutaneous adnexal tumor with differentiation toward the hair germ epithelium. All cases in their study displayed a unique constellation of histological features which allowed the authors to consider the neoplasm to be a distinct entity and to designate it as 'trichogerminoma' (TG). We present a case of an adnexal tumor identical to that described as TG and report the immunophenotypical features of this neoplasm for the first time. A biopsy from a 41-year-old man revealed a well-demarcated epithelial tumor composed of multiple lobules located in the deep dermis without connection to the overlying epidermis and surrounded by a fibrous pseudocapsule. The tumorous lobules were composed of uniform basophilic cells with vesicular nuclei, dispersed chromatin and prominent nucleoli showing no prominent peripheral palisading. Some of the lobules had the appearance of densely packed 'cell balls' with peripheral condensation of the tumor cells. The stroma showed a moderate number of fibroblasts and mast cells. reticulum staining revealed fine reticulum fibers surrounding the tumor aggregates with accentuation of the 'cell balls'. Immunohistochemically, the tumor cells expressed AE1/AE3, CK5/8, CK5/6, CAM5.2 and stained negatively for CK20, CK7, calretinin, Lu-5 and Thomsen- Friedensreich antigen. There was no increase in the numbers of CK20-positive merkel cells in the epidermis overlying the tumor; however, a few merkel cells were scattered in some tumor lobules. In addition, we stained 6 trichoblastomas (TBs) and found a particular pattern of calretinin expression in this tumor which was not observed in our case of TG. We conclude that pathological features allow the delineation of TG as a distinct adnexal neoplasm. Histological differential diagnosis includes basal-cell carcinoma (pilar type), large nodular TB, trichoblastic fibroma, trichoepithelioma, tricholemmoma, pilomatricoma and matrical carcinoma. ( info) |
9/27. A tumor with composite pilo-folliculosebaceous differentiation harboring a recently described new entity--melanocytic matricoma. We report on a case of a peculiar tumor of the pilosebaceous unit showing a composite histologic appearance. The case presented as a pigmented crusted lesion on the back of the nose of a 62-year-old woman with markedly sun-damaged skin. Histologically, the superficial portion of the neoplasm was composed of buds and nests of basaloid epithelium with varying degrees of pilar and sebaceous differentiation. Adjacent to this component, lobules of squamous cells with cytoplasmic glycogenation suggesting the mature outer root sheath were seen. In the underlying dermis, there was a well-defined nodular proliferation composed of variably pigmented basaloid matrical cells forming clusters of "shadow" or "ghost cells" admixed with numerous melanized dendritic melanocytes; this last component of the neoplasm was identical to a recently described entity, melanocytic matricoma. The small size, circumscription, and absence of necrosis favored benignity, although the cytologic atypia of matrical cells did not exclude malignancy. The case is interesting not only because it is the third reported case of a peculiar neoplasm imitating the epithelial-melanocytic interaction in the embryonal hair follicle or bulb of the anagen follicle but because the part resembling melanocytic matricoma presented as a component of a complex lesion. We believe that sunlight may have played a role in the development of this peculiar neoplasm. ( info) |
10/27. Melanotrichoblastoma: immunohistochemical study of a variant of pigmented trichoblastoma. Trichoblastomas (TBs) are benign skin tumors recapitulating the differentiation of hair follicles. Several pathologic variants have been described, including the rare pigmented TB. We report a deeply pigmented nodular tumor excised on the scalp of a 32-year-old African woman, which was clinically suggestive of blue nevus or melanoma. Histologically, the tumor presented features of TB, remarkable by virtue of heavy melanin deposits found within and around tumor nests. By immunohistochemistry, abundant dendritic melanocytes with features of hair follicle melanocytes (expression of S100 protein, tyrosinase, and, most importantly, gp100/HMB-45) were found within the tumor masses. By analogy with melanoacanthoma, a tumor consisting of a combined proliferation of epidermal keratinocytes and melanocytes, we called this tumor "melanotrichoblastoma" and view it as a peculiar variant of (pigmented) TB. ( info) |