Yoshihiro Miura

Merkel cell-poor trichoblastoma with basal cell carcinoma-like foci.

We reexamined 11 cases of trichoblastoma, and two cases of trichoblastoma with basal cell carcinoma (BCC)-like foci were found. In these two trichoblastomas with BCC-like foci, the BCC-like foci were often localized in peripheral or deep areas of lesions extending out of the fibrocytic stroma. Immunohistochemistry was performed in five conventional trichoblastomas and in two trichoblastomas with BCC-like foci, using antibodies against CK20 and CK15. No CK20-positive Merkel cells and no expression of CK15 were seen in any neoplastic aggregations of the two trichoblastomas with BCC-like foci. In contrast, increased numbers of Merkel cells and positive staining for CK15 were observed in all five trichoblastomas without BCC-like foci. The five trichoblastomas without BCC-like foci included two trichoblastomas with a popped out or shelled out appearance, which characteristically had a thick fibrous capsule surrounding the fibrotic stroma, demonstrating numerous Merkel cells in the aggregations. Some trichoblastomas may undergo mutations, resulting in the development of foci of BCC and in the loss of the expression of CK15 as well as the disappearance of Merkel cells.

The occurrence of two types of amyloid in the same patient

M. D’ INCAN J . JOUB ER T* J . KAN I TAK I S M. SALAV ERT O. TOURN I LHAC F . MA I TR E§ P . D É CHE LOTT E* P . SOUT EYRAND E . E S T È V E– L . MART IN– Departments of Dermatology, *Pathology and Haematology, CHU Clermont-Ferrand, Hôtel-Dieu, F-63058 Clermont-Ferrand, France Departments of Dermatology and Electron Microscopy, CHU Lyon, Edouard Herriot Hospital, F-69347 Lyon, France Departments of §Pathology and –Dermatology, CHG Orléans, La Source Hospital, F-45000 Orléans, France Correspondence: Michel D’Incan. E-mail: mdincan@chu-clermontferrand.fr

Atrophic dermatofibrosarcoma protuberans with diffuse eosinophilic infiltrate

Atrophic dermatofibrosarcoma protuberans (atrophic DFSP) is a variant of dermatofibrosarcoma protuberans (DFSP), and is clinically characterized by depressed lesions. We report a patient with a typical atrophic DFSP lesion with marked eosinophilic infiltration. The patient was a 55‐year‐old woman with a dark‐red, depressed lesion in the epigastric region. Histopathological examination of the lesion showed proliferation of fibroblast‐like cells in a storiform pattern in the dermis and subcutaneous tissue. Immunohistochemical staining of tumor cells was positive for CD34. The lesion was histopathologically typical of DFSP, but no elevated lesion was clinically observed. Thus, a diagnosis of atrophic DFSP was made. Moreover, this tumor tissue exhibited marked eosinophilic infiltration. To our knowledge, they are no reports of eosinophilic infiltration in DFSP tissue. Therefore, this seems to be an extremely rare case of DFSP.

Epithelioid cell histiocytoma with underlying artery damage

Although epithelioid cell histiocytoma is considered a variant of fibrous histiocytoma (dermatofibroma), the histogenesis of this condition remains controversial. A recent investigation suggested the possibility that epithelioid cell histiocytoma is an angioformative fibrous histiocytoma. We report a case of epithelioid cell histiocytoma underlying a damaged artery. This epithelioid cell histiocytoma with a central area of hemorrhage was associated with a medium‐sized artery in the reticular dermis running vertically up to the lesion. Both the artery in the reticular dermis and its centrally branched artery in the subcutaneous tissue showed mural injury and intraluminal epithelioid endothelial proliferation. Immunohistochemically, the labeling rate for each of the antibodies studied in the epithlioid cells was as follows: 40% for Factor XIIIa, 5% for CD34, 20% for factor VIII‐related antigen, and 10% for α‐smooth muscle cell actin. This case may support the view that epithelioid cell histiocytoma is a vascular and angioformative fibrous histiocytoma.

Extramedullary plasmacytoma of the testis which formed cutaneous tumors

78歳男性。1992年右陰嚢腫大が出現し, 9年後に腹部, 左側胸部に腫瘤が出現した。さらに翌年, 左眼瞼下垂が出現し, CT上頭蓋内に病変を認めたため入院となった。腹部と左側胸部に紫紅色, 弾性硬の腫瘤を, 眼所見では両側眼瞼下垂と左動眼神経麻痺を認めた。血液検査では総蛋白の増加, 蛋自分画でM-蛋自陽性だった。骨髄穿刺所見で異常はなかった。病理組織所見では真皮上層から皮下組織にかけてびまん性に細胞浸潤を認めた。腫瘍細胞は軽度異型性を示し, 車軸様の核を有するなど形質細胞の特徴を有していた。免疫組織学的に腫瘍細胞は形質細胞マーカーに陽性を示した。遺伝子再構成は免疫グロブリンJHで認めた。精巣腫瘤も同様の所見を示したことから精巣原発の髄外性形質細胞腫と診断した。治療は放射線療法と化学療法を併用し, 一時縮小したが, 9ヵ月後に腫瘤が再び増大, 背部や膝窩に多発してきたため, 外科的切除と化学療法を併用した。