Tatsushi Shiomi

Perivascular myoma: Case report with immunohistochemical and ultrastructural studies

A subcutaneous myopericytoma‐type perivascular myoma arising in the elbow of a 61‐year‐old woman is described. The tumor was well demarcated and consisted microscopically of small ovoid and spindle cells arranged in a concentric fashion, surrounding small to medium‐sized vessels and imparting a superficial resemblance to hemangiopericytoma. In some areas, the cellular whorls were separated by myxoid stroma. Cells located between cellular whorls appeared immature with scant cytoplasm but did not show distinct nuclear anaplasia, increased mitoses or foci of necrosis. Immunohistochemistry showed that constituent cells were positive for α‐smooth muscle actin and desmin. Electron microscopy disclosed that the immature‐looking cells, as well as the ovoid and spindle‐shaped cells, possessed focal densities along with thin filaments, subplasmalemmal densities, pinocytotic vesicles and an external lamina. These ultrastructural and immunohistochemical features indicate a myoid nature of pericytic cells and justify this type of neoplasm being categorized as perivascular myoid tumor.

Poikilodermatous mycosis fungoides with a CD8+ CD56+ immunophenotype: a case report and literature review.

Mycosis fungoides (MF) represents the most common type of cutaneous lymphoma. MF shows varieties in both its clinical presentation and immunophenotype. We herein report one case of poikilodermatous MF with a CD8+ CD56+ immunophenotype and present a literature review. A 20‐year‐old Japanese woman presented with a 10‐year history of multiple poikilodermatous and reddish or brownish patches with mild pruritus on the chest, abdomen, back, buttock and thighs. Histopathologically, small‐ to medium‐sized atypical lymphocytes infiltrated into the epidermis, indicating epidermotropism, along the basal layer, and distributed in band‐like appearance in the papillary dermis. Immunohistochemically, atypical lymphocytes expressed CD3, CD8, CD56, T‐cell intracellular antigen (TIA)‐1, granzyme B and beta F1 but lacked expression of CD4, CD20, CD30 and Epstein‐Barr virus (EBV) latent membrane protein 1. An EBV‐encoded small non‐polyadenylated RNA‐1 (EBER‐1) signal was not detected. On the basis of these findings, the diagnosis of CD8+ CD56+ MF was established. Poikilodermatous MF with a CD8+ CD56+ immunophenotype, as presented herein, is extremely rare. Although further investigation is needed to fully clarify the nature of this aberrant phenotype of MF, we stress that it is important to recognize this rare immunophenotype of MF to distinguish it from aggressive cytotoxic cutaneous lymphomas.

Extramammary Paget’s disease: Evaluation of the histopathological patterns of Paget cell proliferation in the epidermis

Extramammary Paget’s disease (EMPD) is a rare malignant skin neoplasm. The prototypical pattern of tumor cell proliferation in the epidermis includes single cells and/or nest arrangements, mainly in the lower epidermis. Although other patterns have been recognized, they have not previously been investigated in detail. We aimed to examine the patterns of tumor cell proliferation in the epidermis. Surgical specimens were obtained from 38 patients with primary EMPD. We defined six patterns, in addition to the prototypical one: (i) glandular; (ii) acantholysis‐like; (iii) upper nest; (iv) tall nest; (v) budding; and (vi) sheet‐like. There were 26 males and 12 females (mean age, 75.0 years). Lesions were located on the scrotum (26 cases) and vulva (12). There were 22 in situ EMPD and 16 invasive EMPD. The frequencies of the different proliferation patterns were: glandular, 36.8%; acantholysis‐like, 73.7%; upper nest, 68.4%; tall nest, 28.9%; budding, 47.4%; and sheet‐like, 23.7%. Upper nest pattern and the presence of more than three patterns were significantly more frequent in invasive EMPD than in situ EMPD (P < 0.05). We identified the histopathological patterns of Paget cell proliferation in the epidermis in EMPD, and suggest that the characteristic patterns and the diversity of patterns could be associated with progression and dermal invasion in EMPD.

Pigmented Dermatofibrosarcoma Protuberans and Blue Naevi with Similar Dermoscopy: A Case Report.

A 71-year-old Japanese woman was referred to our department for evaluation of 3 pigmented lesions on her left buttock. She had been aware of the lesions for a few months. Physical examination revealed 3 blue nodules, approximately 7, 8 and 4 mm in diameter, located on the left buttock (Fig. 1a). Dermoscopic examination revealed a homogeneous blue pigmentation with whitish-veil structures in each of the 3 lesions (Fig. 1b). However, the colour of the upper lesion was paler than that of the other lesions. Based on these findings, we suspected that these were blue naevi. The middle lesion was resected under local anaesthesia. Histopathological examination revealed diffuse proliferation of spindle cells containing melanin granules in the lower dermis (Fig. 1c). A diagnosis of cellular blue naevus was made. The remaining 2 lesions were not resected, and a wait-and-see approach was taken. After 2 years, the patient became concerned about the remaining 2 lesions, and returned to our department for treatment. The 2 blue nodules were slightly increased in size on the left upper and lower buttocks (Fig. Sla1). There was no change in dermoscopic features compared with those seen 2 years previously (Fig. Slb1). The 2 lesions were resected under local anaesthesia. The diagnosis of the lower small lesion was blue naevus. Histopathologically, the other lesion on the upper buttock showed massive proliferation of atypical spindle-shaped cells arranged in a storiform pattern from the lower dermis to the subcutaneous adipose tissue. In addition, there were scattered dendritic cells containing granular melanin pigments (Fig. Slc1, Sld1). Immunohistochemically, the spindle tumour cells were positive for CD34 (Fig. S1e1), but negative for S-100 protein, while dendritic cells were only positive for S-100 protein (not shown). A diagnosis of Bednar tumour (pigmented dermatofibrosarcoma) was made. An additional extensive resection with a 3-cm tumour Pigmented Dermatofibrosarcoma Protuberans and Blue Naevi with Similar Dermoscopy: A Case Report

A brownish-grey plaque with ulceration on the nasolabial area: a quiz. Microcystic adnexal carcinoma.

A 57-year-old Japanese man presented with a 10-year history of a plaque on his face. The lesion had gradually increased in volume. Physical examination revealed a brownish-grey plaque, approximately 5 × 5 cm in size, with ulceration on the right nasolabial area (Fig. 1a). Dermoscopy showed a milky-red area with some milia-like cysts and dilated vessels on the surface (not shown). Histo pathological examination revealed a poorly circumscribed tumour invading deeply into the dermis and subcutis. Tumour nests composed of atypical basaloid cells were embedded in a desmoplastic stroma. Some keratinous cysts and cystic glands were seen in the mid-dermis. Small ductal or glandular structures were also seen in the deep dermis (Fig. 1 b, c). Immunohistochemically, most of tumour cells were positive for carcinoembryonic antigen (CEA).