To the Editor.—
Several causes of elevated serum acid phosphatase are known, including metastatic carcinoma of the prostate, Gaucher's disease, thrombocytosis, multiple myeloma, and others. Helen Woodard has written extensively about the acid phosphatases. I have seen a patient with a markedly elevated acid phosphatase level due to, as far as I know, a previously unreported cause.A 24-year-old nurse was seen in employees' clinic for headaches of a migraine-like nature, and found to be hypertensive. She had a family history of thyroid disease, "stomach tumors," and was found to have several abnormalities in the laboratory findings, including a mild hypercalcemia, mildly elevated alkaline phosphatase level, and an acid phosphatase level, repeated on several occasions, that was ten times greater than normal. She also had a markedly elevated 5-hydroxyindoleacetic acid. The only abnormality on physical examination was a small breast nodule.Surgery revealed a hibernoma of the breast and a