1/22. 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.- - - - - - - - - - ranking = 1keywords = melanocytic, pigmented (Clic here for more details about this article) |
2/22. Acquired partial curly hair.We report 6 adolescent females apparently affected by diffuse partial woolly hair. The patients complained of thinning and curling of some hair of the scalp. Examination revealed two distinct hair populations. The first hair population was straight, normally pigmented and of normal length, thus considered "normal" hair. The second hair population was wavy, curly, thinner and apparently slightly shorter, thus considered abnormal. Direct examination of the abnormal hair population under a light microscope revealed a curled pattern of the hair shaft, and single torsions. With light microscopy the clinically normal hair had no abnormalities. Under scanning electron microscopy (SEM) the abnormal hair had curly and flattened hair shafts of 30-60 mum in diameter, oval shaped sections, canalicular formations, single torsions and cuticular weathering. With SEM, clinically "normal" hair had a diameter between 60-80 mum, with no major relevant abnormalities except for weathering. These results are suggestive of a new variant of acquired kinking (curling) of hair simulating diffuse partial woolly hair. The absence of clinical alterations in the proximal area of the affected hair and the spontaneous improvement with time, suggests that this variant may result from environmental exposure (weathering, cosmetic procedures) in predisposed individuals.- - - - - - - - - - ranking = 0.023238341711377keywords = pigmented (Clic here for more details about this article) |
3/22. Combined cutaneous hamartoma encompassing benign melanocytic naevus, vellus hair cyst and epidermoid cyst.We describe a combined cutaneous hamartoma in a 57-year-old man, which comprised a vellus hair cyst, an epidermoid cyst and an intradermal melanocytic naevus in a single facial tumour. The vellus hair cyst was filled with keratinous material with unusual slit-like lacunae. While numerous cases of epidermoid cyst have been reported in association with an intradermal melanocytic naevus, our case is a rare example of a lesion combining several hamartomatous elements.- - - - - - - - - - ranking = 3.8204586904234keywords = melanocytic, naevus (Clic here for more details about this article) |
4/22. 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.- - - - - - - - - - ranking = 3.2211398994635keywords = melanocytic, pigmented (Clic here for more details about this article) |
5/22. 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.- - - - - - - - - - ranking = 0.16266839197964keywords = pigmented (Clic here for more details about this article) |
6/22. Pigmented terminal hair cysts within an intradermal melanocytic naevus.The combination of melanocytic naevi and cysts of adnexal or epithelial origin has been described previously. Herein we describe a case of intradermal melanocytic naevus containing pigmented terminal hair cysts, a rare variant of epithelial cysts. Our observation suggests that pigmented follicular cysts and combined cystic-melanocytic lesions may be attributed to follicular occlusion.- - - - - - - - - - ranking = 4.1372388919301keywords = melanocytic, naevus, pigmented (Clic here for more details about this article) |
7/22. Melanocytic matricoma: case confirmation of a recently described entity.BACKGROUND: In 1999, Carlson et al. reported two cases of a matrical neoplasm that recapitulates the bulb of the anagen hair follicle, which they designated as melanocytic matricoma. methods: Here we report a similar case in a 78-year-old white male, who presented with a 0.4 cm purple-black firm papule in the left preauricular area. RESULTS: Histologically, the tumor is composed of a dual cell population including admixed epithelial matrical and supramatrical cells with "shadow" cell formation and pigmented dendritic melanocytes. Immunohistochemical studies for cytokeratin highlighted the epithelial component and studies for S-100 protein, HMB-45, and vimentin confirmed the melanocytic component. The differential diagnosis considered includes pigmented variants of pilomatricoma, matrical carcinoma, basal cell carcinoma and malignant melanoma. CONCLUSIONS: The case reported herein is the first confirmation of melanocytic matricoma, a distinctive adnexal neoplasm with characteristic clinical and pathologic features, which differentiate it from pigmented pilomatricoma.- - - - - - - - - - ranking = 1.4302849748659keywords = melanocytic, pigmented (Clic here for more details about this article) |
8/22. Matrical carcinoma with prominent melanocytic hyperplasia (malignant melanocytic matricoma?) A report of two cases.Melanocytic matricoma is a recently described lesion characterized by well-circumscribed nodules composed of matrical and supramatrical cells with clustered ghost cells, and admixed pigmented dendritic melanocytes, with no cyst formation or connection to the epidermis or pre-existing hair follicles. Although variable cytologic atypia and frequent mitoses in the epithelial component may be present, given the well-defined margins and absence of tumor recurrences, these lesions were initially considered benign neoplasms, and not matrical carcinoma. Theoretically, the detection of numerous melanocytes in matrical carcinoma should not be surprising, but is in fact a very unusual feature. A case with extensive melanization of epithelial elements and only rare melanocytes has been reported. We report two cases of matrical carcinoma with prominent melanocytic hyperplasia, with emphasis on the ultrastructural and immunohistochemical features. Our cases might be considered the malignant counterpart of the so-called melanocytic matricoma.- - - - - - - - - - ranking = 4.5584715074838keywords = melanocytic, pigmented (Clic here for more details about this article) |
9/22. CD34-reactive trichodiscoma.BACKGROUND: Trichodiscomas are rare hamartomas of the dermal portion of the hair disc, a specialized component of the perifollicular mesenchyme. They are usually found as asymptomatic multiple skin-colored papules on the face and extremities and may have an autosomal dominant inheritance pattern. However, a solitary variant has been described. CASE REPORT: A 78-year-old woman presented with a single, non-pigmented, firm papule on the left tip of the nose, measuring 3.5 mm in diameter. RESULTS: The histological examination revealed the previously described features of a trichodiscoma. The immunohistochemical analysis showed strong immunoreactivity for CD34 in the spindle cell component. Spindle cells were negative for S-100, HMB-45, Melan-A, EMA, neurofilament, desmin, and Factor XIIIa by immunohistochemistry. CONCLUSIONS: We report strong reactivity for CD34 in the spindle cell component of a trichodiscoma. We suggest that this lesion be considered in the differential diagnosis of any CD34 dermal spindle cell proliferation, in which an adjacent epithelial component cannot be entirely excluded.- - - - - - - - - - ranking = 0.023238341711377keywords = pigmented (Clic here for more details about this article) |
10/22. Congenital panfollicular nevus: report of a new entity.The various forms of non-melanocytic nevi (hamartomas) are usually encountered in pediatric patients, and nevus sebaceous of Jadassohn is the most common to have undifferentiated pilosebaceous units. We report a unique congenital follicular nevus that fails to meet the criteria of any previously described follicular neoplasm, despite the plethora of alternatives. Clinically considered a syringocystadenoma papilliferum, the excised lesion contained multiple dermal nodules that exhibited nearly all stages of follicular differentiation. The periodicity of the follicular proliferations was akin to normal terminal hair, and a prominent perifollicular sheath surrounded each. This benign lesion of abortive hair follicles was unassociated with any established genodermatous syndrome or other adnexal neoplasm.- - - - - - - - - - ranking = 0.45352331657725keywords = melanocytic (Clic here for more details about this article) |
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