Incidence, structure, and function of enlarged parathyroid glands discovered accidentally during thyroid surgery.
BACKGROUND
Operation on rare patients with mainly a severe renal stone disease and considerably elevated urinary calcium excretion has substantiated the association of parathyroid gland abnormalities with normocalcemia. This study examines incidence, structure, and functional characteristics of enlarged parathyroid glands of patients with normocalcemia scheduled for thyroid surgery.


METHODS
Eleven enlarged parathyroid glands weighing 110 to 1000 mg were discovered in 9 (1.5%) of 594 patients with normocalcemia undergoing thyroid operation. The preoperative total serum calcium concentration was 2.30 to 2.52 mmol/L and less than 2.38 mmol/L in four of the nine patients. Intact serum parathyroid hormone and alkaline phosphatase levels were elevated in only one individual, and all patients showed normal serum creatinine values.


RESULTS
All but three of the 11 enlarged parathyroid glands exhibited microscopic abnormality on routine histopathologic examination, including staining for cytoplasmic fat with oil red 0. Immunohistochemical staining with a monoclonal antibody recognizing the functionally important calcium receptor of the parathyroid cell surface and analysis of the calcium-regulated cytoplasmic Ca2+ concentration of dispersed parathyroid cells substantiated that only a single gland of 130 mg had no discernible functional abnormality.


CONCLUSIONS
The findings underline the diagnostic difficulties of parathyroid histopathology and support the presence of disturbed parathyroid hormone secretion even in normocalcemic patients with enlarged parathyroid glands. The functional derangement of these glands substantiates the indication for their surgical excision even in patients exhibiting midnormal serum calcium concentrations, although their possible contribution to the development of a clinically overt hyperparathyroidism can only be speculated.
Department of Surgery, University Hospital, Uppsala, Sweden.
P
P
Hellman
U
U
Ohrvall
C
C
Rudberg
G
G
Bjerneroth
C
C
Juhlin
L
L
Grimelius
P
P
Ridefelt
G
G
Akerström
J
J
Rastad
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000209:etiology; D006984:Hypertrophy; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000473:pathology*; D010281:Parathyroid Hormone / Q000378:metabolism; D013961:Thyroid Gland / Q000601:surgery
D010281:Parathyroid Hormone; D002118:Calcium