Hydralazine use can be associated with IgM-dominated immune complex-mediated glomerulonephritis.

CONTEXT: IgM-dominant immune complex-mediated glomerulonephritis (IgM-dominant ICMGN) is a rare renal entity, characterized by a membranoproliferative pattern by light microscopy, dominant IgM staining by immunofluorescent staining, and subendothelial deposits by electron microscopy. This study was to investigate if some of IgM-ICMGN were associated with autoimmune disorders induced by hydralazine. DESIGN: Seven IgM-dominant ICMGN cases were identified over 8 years. Their pathologic phenotypes and clinical scenarios were analyzed in detail. RESULTS: Patients' ages ranged from 47 to 87 years old with 5 women and two men. Six of seven patients had drug-induced autoimmune phenomenon (hydralazine-induced positive ANCA and ANA). All of them had renal dysfunction and some proteinuria. Most pathologic features showed a membranoproliferative pattern of glomerulonephritis with dominant IgM deposits at subendothelial spaces. IgM nephropathy (a variant of focal segmental glomerulosclerosis), chronic thrombotic microangiopathy, and cryoglobulinemic glomerulopathy were ruled out in the cases. CONCLUSION: The hydralazine-induced autoimmune phenomenon can be seen in IgM-dominant ICMGN, which should be classified as a subtype of membranoproliferative glomerulonephritis.

The Role of Bone Marrow Biopsy Evaluation in the Workup for Monoclonal Gammopathy of Renal Significance: A Diagnosis of Exclusion.

CONTEXT.­: Monoclonal gammopathy of renal significance (MGRS) is a relatively new concept for patients with renal monoclonal protein deposition (RMPD) (except monoclonal cast nephropathy) and has been used as a reason for nephrologists to obtain a bone marrow biopsy (BMB). It takes a team of pathologists and clinicians to determine when RMPD at our institution can be defined as MGRS. OBJECTIVE.­: To identify the proportion of various subtypes of tentative MGRS diagnosed by renal biopsy that can be confirmed as final MGRS after BMB. DESIGN.­: One hundred thirty kidney biopsies with variants of RMPD were identified during the past 10 years. Biopsy cases with known myeloma, B-cell lymphoma, or monoclonal cast nephropathy were separated as a heavy-burden group. The remaining biopsies with RMPD were considered tentative MGRS. Their BMB and clinical indices were further analyzed to determine the final percentage of MGRS diagnoses. RESULTS.­: Among the 130 renal paraprotein deposition cases, 44 (33.8%) were categorized as the heavy-burden group. In the remaining 86 cases, 33 (38.4%) with subsequent identification of myeloma (>10% of monoclonal plasma cells) or lymphoma in BMB were further considered as heavy-burden cases. Eighteen cases (18 of 86; 20.9%) did not receive follow-up BMB; thus, no further analysis was performed. BMBs diagnosed as either nonmalignant (no plasma cells; 8 of 86 cases; 9.3%) or premalignant (<10% plasma cells; 27 of 86 cases; 31.4%) were confirmed to be final MGRS (35 of 86; 40.7%). CONCLUSIONS.­: The data indicate that BMB is an important element in the confirmation of MGRS.

Extrapulmonary Sarcoidosis With Multi-Organ Involvement Presenting Primarily as Hypercalcemia.

Sarcoidosis is a highly variable disease. The majority of cases affect the lungs, but they can involve other organs as well. Extrapulmonary sarcoidosis is rare, and it can present in many ways. Therefore, the diagnosis can be challenging. We hereby present a case of a patient presenting with hypercalcemia and diagnosed with extrapulmonary sarcoidosis with multi-organ involvement. This article was previously presented as a meeting abstract at the MI-ACP 2022 Annual Scientific Meeting on October 14, 2022.

Benign phaeochromocytoma presenting with recurrent spells and negative biochemical screening.

A woman in her 40s presented with spells of hypertension, warmth, flushing and bradycardia for more than 1 year. Despite normal plasma metanephrines of 0.48 nmol/L (reference range: <0.50 nmol/L) and normal 24-hour urine metanephrines of 199 µg/day (reference range: 52-341 µg/day), an abdominal CT scan was obtained which revealed a 1.7 × 1.4 cm right adrenal gland nodule. During her next spell, 24-hour urine metanephrines were elevated at 585 µg/day with total metanephrines of 1026 µg/day (reference range: 140-785 µg/day). Subsequent MRI demonstrated a 1.5 × 1.5 cm right adrenal gland lesion concerning for phaeochromocytoma. Right adrenal gland excision was performed and pathology confirmed a benign phaeochromocytoma. Follow-up genetic testing was negative. This case highlights the challenges of identifying phaeochromocytomas in the clinical setting. Early imaging may assist in the timely diagnosis and treatment of these tumours in patients presenting with recurrent spells and negative biochemical screening.