Extremely high parathyroid hormone concentrations associated with pityriasis rubra pilaris and monoclonal gammopathy of unknown significance: a clinical dilemma.
We present a case with extremely high parathyroid hormone (PTH) concentrations in the order of hundred thousands accompanied by dermatological and hematological diseases. After several diagnostic interventions, no malignancy could be demonstrated except monoclonal gammopathy of unknown significance. The dermatological findings were taken to be manifestations of the hematological disease. Since the first serum intact PTH concentration of the patient was found to be higher than 2500 pg/ml, dilution study was performed and found to be 215,977 pg/ml. The high concentration of serum PTH was taken to be falsely high due to assay interference. This concentration was checked from three different paths; a test for linear dilution was performed, the test was repeated with another method and the sample was treated to remove or inhibit interfering substances. The results were compatible with endogenous antibody interference, presumed to be a result of monoclonal gammopathy. The extremely high PTH concentrations were not only due to assay interference, but also secondary hyperparathyroidism, which was evident by the decrease in PTH concentrations with calcium and vitamin D treatments.
Hacettepe University Faculty of Medicine, Department of Internal Medicine, Ankara, Turkey. mdurusu@hacettepe.edu.tr
Mine Durusu
MD
Tanriover
Oytun
O
Portakal
Asli
A
Hapa
Yasemin
Y
Tekinel
Selcuk
S
Dagdelen
Yahya
Y
Buyukasik
Mustafa
M
Arici
D000368:Aged; D002118:Calcium / Q000627:therapeutic use; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy; D008297:Male; D010265:Paraproteinemias / Q000097:blood* / Q000188:drug therapy; D010281:Parathyroid Hormone / Q000097:blood*; D010916:Pityriasis Rubra Pilaris / Q000097:blood* / Q000188:drug therapy; D014807:Vitamin D / Q000627:therapeutic use
D010281:Parathyroid Hormone; D014807:Vitamin D; D002118:Calcium