Primary plasma cell leukemia (PPCL) is a rare form of multiple myeloma (MM) and is a rare aggressive disease with a median overall survival of 6-11 months. We present a case of acute hyperammonemic encephalopathy as the initial presentation of PPCL in a 78-yearold woman to highlight an atypical presentation of this disorder.

A 40-year-old male smoker with HIV was admitted for cough, hypotension, and abdominal pain for 5 days. Chest radiography showed a right lower lobe consolidation. CT of the chest, abdomen, and pelvis revealed paratracheal adenopathy, a 5.8×4.5 cm mass invading the right bronchus intermedius, and dense bilateral adrenal masses, measuring 5.4×4.0 cm on the right and 4.8×2.0 cm on the left. Laboratory studies showed white blood cell count of 18.5 K/mm3, sodium of 131 mmol/L, creatinine of 1.6 mg/dL, and CD4 count of 567 cells/mm3. The random morning cortisol level was 7.0 μg/dL, the ACTH stimulation test yielded inappropriate response, and a random serum ACTH was elevated at 83.4 pg/mL. MRI brain revealed no pituitary adenoma confirming primary adrenal insufficiency. The adrenal CT washout study was consistent with solid mass content, concerning for metastasis. Bronchoscopy with endobronchial mass and paratracheal lymph node biopsy confirmed small-cell lung cancer (SCLC). Intravenous steroids, 100 mg hydrocortisone every 8 hours, improved his hypotension and abdominal pain. PET scan revealed metabolically active right paratracheal mass, right hilar mass, and bilateral adrenal masses. Treatment included palliative chemotherapy consisting of carboplatin/etoposide/atezolizumab and chest radiation. We present this novel case to demonstrate SCLC’s ability to cause primary adrenal insufficiency, as well as evaluate clinical response to chemotherapeutics.