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.
Thomison
John
J
Department of Pathology, University of Colorado Health Sciences Center, Denver, CO, USA.
McCarter
Martin
M
McClain
Damon
D
Golitz
Loren E
LE
Goldenberg
Gary
G
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