Stones, moans and groans: a clinicopathological case report of sarcoidosis in the kidney

Abstract

Sarcoidosis is characterised by idiopathic, disordered immune regulation and presents as non-caseating granulomatous inflammation progressing to fibrosis, which can occur systemically and affect multiple organs. The incidence occurs in 1-40:100 000, with a higher predilection in the female population within the second to fourth decades of life. Serum ACE, hypercalcaemia and hypercalciuria are supportive of the diagnosis, as well as a constellation of clinical presentations from cutaneous, neurological and endocrine manifestations. Renal involvement is rarely the primary presenting pathology, and occurs within 10-20% of cases, associated with acute kidney injury, or chronic kidney disease. These manifest as glomerular, tubular and interstitial dysfunctions, with tubular dysfunction leading to abnormal calcium metabolism. Histologically, Schaumann bodies (intracellular calcific bodies) and asteroid bodies (stellate cytoplasmic inclusions) can be seen within epithelioid histiocytes and multinucleated giant cells. Here we present a case of 55-year-old female presenting with multiple renal calculi with classic loin-to-groin pain and haematuria, with acute kidney injury, with a previous history of bilateral renal colic. We further discuss clinical relevance of the histological diagnosis, the literature on relevant ancillary tests with imaging features of further clinical complications, clinical progression, and prognosis of the entity.