Computed tomographic and pathological findings of dermatofibrosarcoma protuberans

The aim of the study was to investigate the computed tomographic (CT) and pathological findings of dermatofibrosarcoma protuberans to improve the awareness and understanding of the tumors from aspect of CT images.

The CT findings of 16 cases (17 tumors) with dermatofibrosarcoma protuberans confirmed by pathological findings were retrospectively selected. Fourteen cases were primary dermatofibrosarcoma protuberans, 2 cases were recurrent tumors. Thirteen patients had CT plain and enhanced scans, 1 patient had direct enhanced CT scan, 2 patients had only unenhanced scan. Images of the tumors were analyzed and compared with pathological results.

Of the 16 cases (17 tumors total), 9 cases were on the trunk, 7 cases were on the head and the neck; 15 cases appeared as solitary isohypodense, ovoid, or round mass at the cutaneous and subcutaneous tissue, 1 case demonstrated 2 isodense masses on unenhanced CT images. The mean diameter of tumors was 4.0 cm, and the depth was 1.7 cm. The margin was well defined (n = 15 [88.2%]) or ill defined (n = 2 [11.8%]). Fifteen tumors revealed moderate or marked homogeneous (n = 12 [80%], smaller lesion, diameter <5 cm) or heterogeneous (n = 3 [20%], larger lesion, diameter ≥5 cm) enhancement on enhanced CT with intratumoral nonenhancement areas, which indicated intratumoral necrotic and cystic degeneration areas. No calcifications and metastasis were found. The histological examinations revealed large amounts of uniform spindle cells, which were arranged in "storiform" pattern. Immunohistochemical analysis revealed samples positive for CD34 and vimentin.

The common imaging findings of dermatofibrosarcoma protuberans include a solitary, superficial, subcutaneous solid mass, various homogenous or heterogeneous enhancements due to degenerative areas. Computed tomographic scan is helpful to detect the size, location, depth and range of this tumor.