Pigmented Trichoblastoma

Department of Dermatology, University of Turin, Italy.
American Journal of Dermatopathology (Impact Factor: 1.39). 09/1992; 14(4):345-9. DOI: 10.1097/00000372-199208000-00010
Source: PubMed


We report a case of trichogenic tumor with epithelial and mesenchymal components recapitulating the formation of hair germs. The epithelial lobules were highly pigmented and affected the full thickness of the dermis, extending into the subcutaneous fat. In addition, amyloid deposits were found within the epithelial lobules and in the stroma. The overall architecture was reminiscent of hair bulbs. Problems of differential diagnosis with other trichogenic tumors and pigmented tumors are discussed.

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    ABSTRACT: Zusammenfassung. Es wird eine kurze Übersicht über Tumoren mit follikulärer Differenzierung gegeben und ein besonderer Schwerpunkt auf das Trichoblastom gelegt. Headington teilte 1970 die Tumoren des Haarkeimes (trichogene Tumoren) in den reinen epithelialen Tumor ohne induktive Veränderung des Mesenchyms (Trichoblastom), in den gemischten epithelial-mesenchymalen Tumor mit induktiven Veränderungen (trichoblastisches Fibrom), in den gemischten epithelial-mesenchymalen Tumor mit Ausbildung von fortgeschrittenen Haarfollikelstrukturen (trichogenes Trichoblastom) und in den vorwiegend mesenchymalen Tumor mit fortgeschrittener Ausbildung einer abortiven dermalen Haarpapille (trichogenes Myxom) ein. Ackerman et al. schlugen 1993 eine Vereinfachung dieser Einteilung vor und bezeichneten jeden Tumor mit follikulärer Differenzierung, dessen Gutartigkeit durch seine Architektur (Symmetrie, Abgrenzbarkeit, vertikales Wachstum) definiert ist und der ein Vorherrschen von follikulären germinativen Zellen zeigt als Trichoblastom. Diese Auffassung gewinnt bei den Dermatohistologen zunehmend an Bedeutung, ohne daß dieser Begriff bei den klinisch tätigen Dermatologen eingeführt ist. Die klinische Dignität dieses Tumors läßt sich noch nicht abschließend beurteilen.
    Der Hautarzt 02/1995; 46(2):81-86. DOI:10.1007/s001050050214 · 0.56 Impact Factor
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    ABSTRACT: Trichoblastoma and nodular basal cell carcinoma are generally held to be distinctive epithelial neoplasms with some overlapping features. We investigated 30 trichoblastomas in which the basaloid cells expressed cytokeratins (CK) CK5/6, CK14, CK17, CK19, and, in a few cells, vimentin. The cells of the periphery of small and large cysts showed the same profile. Cells lining the lumen of small cysts expressed CK14, CK17, and involucrin, and those in larger cysts showed a positivity for CK1, CK4, CK10, CK14, CK17, and involucrin. The remaining tested antibodies (CK7, CK8, CK13, CK18, CK20, alpha-smooth-muscle actin) were negative in all cases. The cells of the stroma expressed vimentin and in 22 cases, the CD34 antigen. Seventeen nodular basal cell carcinomas showed exactly the same staining pattern. Furthermore, there are striking immunohistochemical similarities between the neoplastic basaloid cells of both neoplasms and the cells of the hair germ. Therefore, trichoblastoma and nodular basal cell carcinoma cannot be distinguished by their pattern of cytokeratin expression in paraffin sections. The virtually identical cytokeratin pattern seen in trichoblastoma, basal cell carcinoma, and the developing fetal hair follicle is compelling evidence for common differentiation pathway.
    American Journal of Dermatopathology 09/1997; 19(4):341-50. DOI:10.1097/00000372-199708000-00005 · 1.39 Impact Factor
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    ABSTRACT: 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.
    American Journal of Dermatopathology 09/1999; 21(4):344-9. DOI:10.1097/00000372-199908000-00006 · 1.39 Impact Factor
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