The value of serum enzyme determinations as an aid in differential diagnosis and for the evaluation of prognosis is well established in a variety of clinical situations.1 Thus, elevations of the serum acid phosphatase, and more specifically of the "prostatic fraction" thereof, have been considered, in general clinical terms, to be related to neoplastic changes in the prostate gland and extension of the neoplasm beyond the capsule of the gland.2-5 Since considerable clinical specificity and importance have been placed on the serum acid phosphatase, it is often assayed as an aid in obtaining an etiologic diagnosis in patients with evidence of bony metastases. The following case is a report of a patient with multiple myeloma with the unusual feature of elevated levels of both total and "tartrate inhibited prostatic fraction" of the serum acid phosphatase, in whom at necropsy no neoplastic change of the prostate gland was demonstrated.
FRENKEL EP, TOURTELLOTTE CD. Elevated Serum Acid Phosphatase Associated with Multiple MyelomaCase Report with Tissue Enzyme Assay. Arch Intern Med. 1962;110(3):345–349. doi:10.1001/archinte.1962.03620210069013