Hypercalcemia is a common complication of cancer with PTHrP an important mediator. Literature on the underlying causes of PTHrP-mediated hypercalcemia, in both malignant and benign conditions, is limited to small case series and case reports. The purpose of this study was to systematically identify a large series of cases of PTHrP-mediated hypercalcemia and to document differences in demographics and the clinical course between malignant and benign etiologies. This was a hospital-based, retrospective case series that identified subjects from 1999 to 2010 from the public hospital system in Queensland, Australia. Included subjects were 18 years and older and had persistent hypercalcemia with simultaneously elevated PTHrP. A total of 138 cases were identified. Solid organ malignancies made up 82.6% (n = 114) of cases, with squamous cell carcinoma (28.2% of total) and adenocarcinomas (27.5%) almost equally as common. Hematological malignancy and benign conditions made up 8.7% (n = 12) each. Squamous cell carcinoma of the lung was the single most commonly identified etiology (10.9%). Causes not previously identified included myxoid sarcoma, plasma cell leukemia, duodenal adenocarcinoma, metastatic Merkel cell carcinoma, and epithelioid hemangioendothelioma. Median survival was different among the groups (52 days [interquartile range, 21-132 days] for solid organ malignancy, 362 days [18-652 days] for hematological malignancy, and 906 days [16 days to undefined] for the apparently benign group; P < .0001). There were no differences in PTHrP among the groups. Although the mean corrected calcium level was lower in the benign group (3.03 mmol/L [2.80-3.29 mmol/L]) compared with that in the solid organ (3.11 mmol/L [2.89-3.46 mmol/L]) and hematological malignancy groups (3.60 mmol/L [3.01-3.79 mmol/L]) groups (P = .046), it was not a useful discriminator of etiology. PTHrP-mediated hypercalcemia is most frequently caused by solid organ malignancy, and it portends a poor prognosis. Although the solid organ malignancy group had the shortest survival, the hematological malignancy and apparently benign causes groups still had relatively short overall survival.

Glucocorticoid resistance is a rare genetic condition characterized by reduced sensitivity to cortisol signaling and subsequent hyperactivation of the hypothalamic-pituitary-adrenal axis. The objective was to confirm the diagnosis of glucocorticoid resistance in the patient, to determine the degree of suppression of cortisol and ACTH levels in response to dexamethasone, and to determine the underlying genetic abnormality and functional consequences of the mutation. The patient presented on the first day of life with profound hypoglycemia. Initial cortisol levels were appropriately elevated; however, the patient was found to have persistently elevated levels of both cortisol and ACTH. The baby developed a tanned appearance and severe hypertension and fatigued easily with feeding. Serial oral dexamethasone suppression tests were performed with doses escalating from 0.125 mg to 12 mg dexamethasone given at 2300 h. Sequencing of the glucocorticoid receptor gene was performed along with functional studies of the glucocorticoid receptor. GH secretion was assessed with an arginine glucagon stimulation test. Cortisol and ACTH levels did not suppress with doses of up to 12 mg dexamethasone. A 2-bp deletion was found at amino acid position 773 of the glucocorticoid receptor ligand binding domain. A complete lack of dexamethasone binding and in vitro biological effect was demonstrated. GH stimulation testing was consistent with GH deficiency. The homozygous mutation in the ligand-binding domain of the glucocorticoid receptor gene resulted in a functionally inactive glucocorticoid receptor and apparent complete glucocorticoid resistance with biochemical GH deficiency.

Context: Hypercalcemia mediated by 1,25-dihydroxy vitamin D (calcitriol) is uncommon, with evidence on etiology limited to small case series or case reports.Objective: The objective of the study was to systematically identify a large series of cases of calcitriol-mediated hypercalcemia and document the presentation, demographics, and clinical course across etiologies.Design, Setting, and Patients: The study was a hospital-based, retrospective case series, identifying subjects from 1999 through 2009 across the public hospital system in Queensland, Australia. All patients aged over 18 years were identified that had persistent hypercalcemia associated with elevated or inappropriately normal calcitriol concentration or elevated serum angiotensin-converting enzyme.Results: A total of 101 cases were identified. Sarcoidosis was the most common etiology (49%), followed by hematological malignancy (17%) and infections (8%). Etiologies not previously described include squamous cell carcinoma of the tongue, ovarian cystadenocarcinoma, and chronic lymphocytic leukemia. Median serum angiotensin-converting enzyme was higher in sarcoid patients compared with all other causes [218 U/L (176–277) vs 155 U/L (110–208), P < .001], but a level above the normal range did not discriminate well between cases of sarcoidosis and other causes (specificity at cutoff of 130 U/L was only 31%). However, a value greater than 250 U/L was highly specific (89%) for sarcoidosis but lacked sensitivity (31%). A calcitriol level greater than 300 pmol/L was not seen in sarcoidosis but was seen with other etiologies. Cases with neoplastic etiologies were older (61.4 ± 11.4 y) than all other subjects (51.7 ± 15.0 y, P = .006).Conclusions: Hypercalcemia mediated by calcitriol remains a rare presentation. In almost half the cases, sarcoidosis was the underlying cause, whereas a third of patients had cancer or systemic infections.