1/6. 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.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |
2/6. Perforating pilomatricoma in a process of total elimination.Perforating pilomatricoma is a rare clinical variant of pilomatricoma. We report a case of pilomatricoma with ulceration indicating total elimination. The lesion consisted mainly of laminating shadow cells surrounded by invaginating epidermis. We believe that this case can be considered within the category of perforating pilomatricoma.- - - - - - - - - - ranking = 0.5keywords = epidermis (Clic here for more details about this article) |
3/6. 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 = 0.5keywords = epidermis (Clic here for more details about this article) |
4/6. Pilomatricoma with a bullous appearance.BACKGROUND: Pilomatricoma is a benign, cutaneous neoplasm with differentiation toward hair matrix. The tumor is usually a deep-seated, solitary, firm nodule with overlying normal epidermis. Pilomatricoma with a bullous appearance is very rare. methods: A 16-year-old Chinese girl with a soft, purplish, translucent bulla on the left shoulder for 6 months and a nodule underlying the bulla is described. RESULTS: The histopathologic findings were consistent with pilomatricoma. There was extraordinary dilation of lymphatic vessels in the overlying dermis, which explains the clinical bullous appearance. The surrounding dermis had an edematous appearance. A Verhoeff-van Gieson stain disclosed the marked reduction of the elastic fibers, and an alcian blue stain was negative. CONCLUSIONS: The patient is diagnosed as bullous variant of pilomatricoma.- - - - - - - - - - ranking = 0.5keywords = epidermis (Clic here for more details about this article) |
5/6. Basal cell carcinoma with matrical differentiation in a transplant patient: a case report and review of the literature.BACKGROUND: Shadow cells, characterized by basaloid squamous cells with a distinct well-defined border and a central unstained area as a shadow of lost nuclei, are characteristic of pilomatricoma, a distinct neoplasm of hair matrix differentiation. The presence of shadow cells within tumor islands composed of follicular germinative cells of an otherwise classic basal cell carcinoma (BCC) has been considered as a distinct diagnostic category of BCC with matrical differentiation. We present a case of BCC with matrical differentiation in a transplant patient. To our knowledge, only 10 cases [Aloi et al. Am J Dermatopathol 1988; 10: 509; Ambrojo et al. Am J Dermatopathol 1992; 14: 293; Sagol et al. East J Med 1999; 4: 37; Kwittken J. Cutis 2002; 69: 57; Kim et al. Yonsei Med J 2003; 44: 523] of BCC showing matrical differentiation have been reported. None have been reported arising on the background of immunosuppression. methods: A 58-year-old male cardiac transplant patient with a nodule on the dorsum of left hand was studied. It arose and enlarged rapidly within a few months, causing irritation and bleeding. The nodule was surgically excised and submitted for histopathologic evaluation. The sections were prepared by hematoxylin and eosin (H&E) method. RESULTS: The H&E-stained sections of the hand lesion revealed multiple nodular masses of basaloid follicular germinative cells. In some areas, there was peripheral palisading and stromal retraction artifact typical of classic BCC. In these areas, the tumor nodules were connected to the epidermis, whereas in others, it extended deep into the reticular dermis to the subcutaneous fat junction. Elsewhere, the majority of the tumor contained a population of shadow cells, similar to those in pilomatricoma, with basaloid-appearing matrical cells in the periphery. Trichohyaline granules were identified in the cytoplasm of many of the peripheral basaloid cells. These granules are one of the characteristic features of follicular matrix differentiation. Mitoses were rare. Areas of cystic degeneration were present throughout the tumor. There was no evidence of an infiltrating growth pattern, lymphovascular invasion, or sarcomatoid growth pattern. CONCLUSION: BCC with matrical differentiation is a distinct pathologic entity and a rare subtype of BCC featuring shadow and matrical cells, typically seen in pilomatricoma, a benign hair matrix neoplasm. This tumor has not yet been reported in an immunosuppressed transplant patient.- - - - - - - - - - ranking = 0.5keywords = epidermis (Clic here for more details about this article) |
6/6. Pilomatricomal horn: a new superficial variant of pilomatricoma.We describe a pilomatricomal horn on the right arm of a 39-year-old man. Although initially the tumor was clinically thought to be a verruca vulgaris, the microscopic features were similar to those found in classic pilomatricoma, except for the epidermal location and the presence of a cutaneous horn. light microscopy showed replacement of the epidermis by basaloid cells, with masses of cornified material containing shadow cells that formed a cutaneous horn. Whereas classic pilomatricoma is confined to the deep reticular dermis or subcutis, the present case represents a unique heretofore unreported epidermal variant of pilomatricoma that pathologists should be aware of to differentiate it from malignant epidermal tumors.- - - - - - - - - - ranking = 0.5keywords = epidermis (Clic here for more details about this article) |