T-cell lymphoproliferative disorder potentially induced by imatinib in a patient with GIST.

BACKGROUND

A 71-year-old male patient was diagnosed as having a KIT-positive gastrointestinal stromal tumor located at the gastric antrum. With no signs of distant metastasis, the patient primarily underwent gastric surgery with antrectomy and Billroth-I-reconstruction. Owing to tumor size and mitotic index, the patient was considered at high risk of tumor relapse and thus was entered into a clinical trial to receive adjuvant imatinib treatment. 4 months after initiation of imatinib treatment, the patient presented with several newly discovered subcutaneous and intra-abdominal tumor lesions. Imatinib treatment had been tolerated well until then.

INVESTIGATIONS

Physical examination, blood tests, biopsies of the subcutaneous tumor lesions, tumor morphology and immunohistochemistry, PCR for the T-cell receptor gamma genes, sequential CT and PET-CT.

DIAGNOSIS

Monoclonal T-cell lymphoproliferative disorder, potentially induced by imatinib.

MANAGEMENT

Imatinib was stopped, after which the tumor lesions spontaneously regressed and, eventually, complete remission was achieved.