Panfolliculoma is a rare follicular neoplasm with differentiation toward both upper (infundibulum and isthmus) and lower (stem, hair matrix, and bulb) segments of a hair follicle. We present an unusual case of cystic panfolliculoma. A 33-year-old Hispanic woman presented with an 8-month history of a 3.0-cm cystic scalp mass. The lesion was excised, and the histologic sections showed a cystic follicular neoplasm that contained corneocytes in basket-woven and laminated array, trichohyalin granules of the inner root sheath, germinative cells, papillae, matrical cells, and "shadow" cells. Cytokeratin 903 and cytokeratin 5/6 immunostains uniformly highlight the tumor cells. Ber-EP4 strongly labels the germinative cells but not the follicular papillae. CD34 labels the surrounding fibrotic stroma and focally the epithelial component.
[Show abstract][Hide abstract] ABSTRACT: Panfolliculoma is a distinctive and unusual benign follicular neoplasm. It shows differ-entiation towards all components of the hair follicle, including the upper and the lower segments. We report two cases of this rare disease. The first patient presented with a painful nodule on the scalp and the second patient had an asymptomatic skin-colored nodule on his left eyebrow. Histopathologic examination of both cases revealed lobular proliferation of solid-cystic follicular structures. The cystic structures contain laminated keratin, indicating infundibular differentiation. The solid tumor part was composed of basaloid germinative cells, matricial cells, and cells with trichohyalin granules, repre-senting inner root sheath differentiation. The range of differentiations was highlighted using immunohistochemical stains, including labeling of cytokeratin 1, 5, 10, 14 (using 34βE12), cytokeratin 5/6, CD34 (outer root sheath), and Ber-EP4 (lower segment of hair follicle). Panfolliculoma should not be confused with trichofolliculoma or trichoblastoma.
[Show abstract][Hide abstract] ABSTRACT: We report 4 cases of an infundibular cyst that histopathologically showed small papillary projections of follicular germinative cells emanating from the basal layer of the cyst wall. Some of these projections branched and formed a reticulated pattern. This cystic lesion is histopathologically distinctive. We propose to designate it as a trichoblastic infundibular cyst because its lining resembles that of an infundibular cyst, yet it has cells that resemble those of the follicular germ in its wall.
American Journal of Dermatopathology 01/2007; 28(6):507-9. DOI:10.1097/01.dad.0000211520.49810.e5 · 1.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma (ES) or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.
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