Incidence of Hypercalcemia in Patients with Malignancy Referred to a Comprehensive Cancer Center
I read with interest the recent article by Dr. Vassilopoulou-Sellin et al.' regarding the incidence of hypercalcemia among cancer patients. The overall incidence of this complication was low in the group studied, occurring most frequently among patients with renal cell and non-small cell lung cancer. Pleural mesothelioma has not been implicated as a cause of this paraneoplastic syndrome. Only three cases have been noted in the literat~re.',~ Review of cases of pleural mesothelioma seen at the Massachusetts General Hospital since 1978 found only one case in an asbestos-exposed former shipyard worker. This case, representing only the fourth instance of hypercalcemia associated with pleural mesothelioma, is described below.
A 75-year-old white male retired shipyard office worker presented to his physician complaining of 4 to 6 weeks of progressive dyspnea on exertion. He denied cough orthopnea, chest pain, anorexia, fever, or weight loss. Chest radiograph revealed a large, mobile, right-sided pleural effusion. Thoracentesis showed an exudative effusion. Cytology and needle biopsy suggested pleural mesothelioma. Subsequent thoracoscopy confirmed the diagnosis of mesothelioma (positive keratin stain and negative staining for carcinoembryonic antigen).
The patient subsequently became increasingly confused and his calcium was found to be 14.7 mg/100 ml, phosphorus 3.5 mg/100 ml, and albumin 2.5 g/100 ml. He had no evidence of metastatic disease outside the thorax or evidence of thyrotoxicosis, adrenal insufficiency, Paget disease, sarcoidosis, or granulomatous disease. Cranial computed tomography showed only generalized atrophy, and lumbar puncture was negative. He was started on intravenous hydration and mithramycin. A bone scan showed generalized increased activity in the axial skeleton compared to appendicular skeleton with no focal area of increased activity. A thoracic spine series showed degenerative changes of the thoracic spine. No lytic or blastic lesions of the thoracic spine were noted. Likewise, a lumbar spine series showed only degenerative changes without other abnormalities. With therapy, the patient's serum calcium level decreased to between 11.0 and 11.5 mg/100 ml. His mental status improved somewhat over the course of his hospital stay, but he died 1 month after admission.
Although pleural mesothelioma is a relatively rare tumor, its incidence is increasing4 Hypercalcemia has only rarely been described among patients with this tumor, with only three prior cases noted in the medical literature. Al-though rare, hypercalcemia should be regarded as a potential complication of pleural mesothelioma.