Fine-needle aspiration biopsy cytology of cutaneous calcinosis in a 74-year-old woman with dermatomyositis on methotrexate therapy: a case report

BACKGROUND: Cutaneous calcinosis (CC) occurs in a variety of rheumatic diseases. Fine needle aspiration biopsy (FNAB) may be used in the office setting to evaluate such soft tissue lesions. For patients on methotrexate (MTX) therapy, methotrexate nodulosis (MN) should be considered in the differential diagnosis. CASE: A 74-year-old Caucasian woman with adult-onset dermatomyositis (ADM) on MTX therapy presented for evaluation of a right breast mass and multiple soft tissue nodules. FNABs of the right breast mass and a left upper extremity nodule both demonstrated benign calcified material. Six months later, the patient returned for evaluation of the persistent right breast mass and repeat FNAB revealed adenocarcinoma. Concurrently, a right hip soft tissue nodule was aspirated, demonstrating benign crystalline debris. MTX therapy was discontinued, and the patient subsequently underwent a lumpectomy of the right breast 1 month after FNAB diagnosis, displaying infiltrative ductal carcinoma. Of note, 2 months after her lumpectomy, MTX therapy was restarted and the patient continues to have adequate control of ADM symptoms with persistent, clinically benign soft tissue calcifications. CONCLUSION: Performing FNAB on soft tissue lesions can obviate needless tissue biopsies of CC in appropriate rheumatology patients, thus avoiding the risks and complications associated with more invasive procedures.