Polymyalgia rheumatica as the first presentation of parathyroid carcinoma.

Sir,

Parathyroid carcinoma is a rare neoplasm. Parathyroid carcinoma accounted for only 0.005% of cases reported to the National Cancer Database between 1985 and 1995.[1] Polymyalgia rheumatica is infrequently the initial manifestation of underlying malignancy.[2]

A 57-year-old female patient presented with weakness and a 2 months history of progressive pain, stiffness involving her bilateral shoulders. She had morning stiffness. Physical examination was unremarkable, except for restriction of shoulder and hip movement due to pain. The patient's laboratory results showed erythrocyte sedimentation rate (ESR) value of 102 mm/h, C-reactive peptide (CRP) value of 12 mg/dl (reference range 0-4 mg/dl), serum calcium (Ca) value of 12.4 mg/dl (reference range 8.4-10.2 mg/dl). Serum parathormone (PTH) was reported as 848 pg/ml (reference range 15-65 pg/ml), and the patient's condition was concluded to be primary hyperparathyroidism. Her parathyroid ultrasonography revealed a well-defined lesion localized at the right lobe inferior pole posterior sized 28 × 22 mm with regularly contour. In parathyroid scintigraphy, the late images taken 2 hours after the injection of 25mCi Tc-99m MIBI revealed focal sestamibi retention in the zone corresponding to the thyroid right lobe lower pole inferior. In the surgical material, sized 6 × 2 × 0.7 cm weighing 4 g, tumor cell clusters penetrating into the capsule and within extracapsular blood vessels were identified. The pathology result was considered as a parathyroid carcinoma. Initially, patient's shoulder pain was thought to be associated with metastatic disease. But, metastasis wasn't detected. The reasons suggesting PMR: First, the patient's age is > 50 years, second, pain and limitation in bilateral shoulder girdle, third, ESR value of >50 mm/h and CRP elevation, also duration of the symptoms longer than 2 weeks.[3] 16 mg/day methylprednisolone therapy was initiated. Patient's complaints were prominently regressed after the second day of treatment. In the second month of PMR therapy, the patient had no complaints and ESR; CRP values were within the normal range. Serum calcium level was value of 9.5 mg/dl, PTH level was value of 62 pg/ml in the twelfth month postoperative follow-up. Prednisolone treatment was discontinued beginning from twelfth month, reducing the dose. At sixth month of follow-up after treatment, symptoms and signs related to PMR did not repeated.

Most patients with parathyroid carcinoma (90%) present with symptoms, including severe hypercalcemia, an elevated serum PTH level, nephrolithiasis or nephrocalcinosis, osteopenia, osteoporosis, pathologic fractures, bone pain, gastrointestinal disturbances, depression, fatigue, or memory disturbance.[1] Polymyalgia rheumatica is a clinical syndrome characterized by pain and stiffness in the neck, shoulders, and hips, fatigue, weight loss and low-grade fever and also rarely presented as a paraneoplastic manifestation. There are no specific diagnostic tests for PMR.[3] Cancer-associated rheumatic disorders may represent a paraneoplastic phenomenon, i.e., occur at a distance from the primary tumor or metastases and be induced by the malignancy through mediators such as hormones, peptides, and antibodies. Case reports present a possible association of polymyalgia rheumatica with breast cancer, colon cancer, lymphoma, acute myeloid leukemia, prostate cancer.[245] Association between parathyroid cancer and PMR has not been reported in the literature previously. We want to emphasize that PMR may present as the first sign of parathyroid carcinoma.