A case of cutaneous myoepithelial carcinoma.
BACKGROUND
Cutaneous myoepithelioma, both benign and malignant, is a rare neoplasm composed of neoplastic myoepithelial cells showing diverse histopathological features, and criteria for discriminating benign or malignant have not been fully clarified.


METHODS
We present a case of cutaneous myoepithelial carcinoma in a 62-year-old woman presenting a solid mass in the right back.


RESULTS
Resected tumor was located in the whole dermis and subcutis. Histopathologically, two different growth patterns were noted: a small-nested or trabecular pattern in the superficial part and a large nodular pattern with extensive central necrosis in the deep part. Tumor cells were all epithelioid, although plasmacytoid and glycogen-rich clear cells were also observed within the large nodules of the deep part. Immunohistochemically, the cells were positive for both epithelial and myogenic markers, suggesting myoepithelial origin. Lymphatic invasion and lymph node metastasis were evident despite inconspicuous atypia and low mitotic rate.


CONCLUSIONS
The final diagnosis was cutaneous myoepithelial carcinoma. At present, it seems to be difficult to predict the behavior of myoepithelioma of the skin and soft tissue, although atypia and high mitotic rate are reported to be associated with local recurrence and metastasis.
Tanahashi
Jin
J
Department of Pathology, Faculty of Medicine, Oita University, Yufu City, Japan.
Kashima
Kenji
K
Daa
Tsutomu
T
Kondo
Yoshiyuki
Y
Kuratomi
Eiji
E
Yokoyama
Shigeo
S
D001415:Back; D015415:Biomarkers; D001706:Biopsy; D015622:Epithelioid Cells / Q000473:pathology; D005260:Female; D015726:Giant Cells / Q000473:pathology; D006801:Humans; D008875:Middle Aged; D009208:Myoepithelioma / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*
D015415:Biomarkers