Isolated histiocytic lymphoma of the spleen causing fever and hypercalcemia.

Differentiating between primary and ectopic or pseudohyperparathyroidism may be difficllt, but certain aspects of the patient's clinical history as well as laboratory tests may be helpful. We present an unusual case report of a patient who had massive splenomegaly secondary to a localized histiocytic lymphoma. On the basis of a lower serum parathormone level for a given serum calcium increase combined with normal serum phosphorous and chloride values, the diagnosis of psuedohyperparathyroidism was made and was confirmed when the patient's serum calcium level and temperature returned to normal following splenectomy.