Hyalinized collagen in a dermatofibrosarcoma protuberans after treatment with imatinib mesylate.
We report a novel histological finding in a dermatofibrosarcoma protuberans (DFSP) after treatment with imatinib mesylate: copious amounts of hyalinized collagen. A 57-year-old female was referred for evaluation and treatment of a 7 x 8 x 10 cm tumor on the right anterior shoulder. Histological evaluation of the incisional biopsy showed a highly cellular dermal neoplasm composed of spindle cells arranged in a storiform pattern with minimal collagen. A CD34 immunohistochemical stain was strongly positive, highlighting atypical spindle cells in the dermis. A diagnosis of DFSP was made and the patient was enrolled in the Southwest Oncology Group trial. She received imatinib mesylate 400 mg per day for 1 year. At the end of therapy, the DFSP decreased in size to 5.5 x 4 x 4 cm. The tumor was excised. Histological evaluation showed a residual dermal neoplasm composed of atypical spindle cells and a copious amount of hyalinized collagen. Areas of necrosis were not seen. A CD34 stain confirmed the presence of residual DFSP, highlighting atypical spindle cells. A procollagen I stain was strongly positive, confirming the presence of abundant collagen in the dermis. A similar finding has been reported in gastrointestinal stromal tumor, which shows deposition of myxohyaline stroma after treatment with imatinib mesylate.
Department of Pathology, University of Colorado Health Sciences Center, Denver, CO, USA.
John
J
Thomison
Martin
M
McCarter
Damon
D
McClain
Loren E
LE
Golitz
Gary
G
Goldenberg
D018952:Antigens, CD34 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D014408:Biomarkers, Tumor / Q000378:metabolism; D003094:Collagen / Q000378:metabolism*; D003131:Combined Modality Therapy; D018223:Dermatofibrosarcoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D006818:Hyalin / Q000378:metabolism*; D000068877:Imatinib Mesylate; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology
D018952:Antigens, CD34; D000970:Antineoplastic Agents; D001549:Benzamides; D014408:Biomarkers, Tumor; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D003094:Collagen