Cryptococcal Pneumonia in Multiple Myeloma: A Case Report.

Patients with multiple myeloma (MM) often experience infections due to aberrant immunoglobulin production by malignant plasma cells and immunosuppressive therapeutic interventions that are used to treat the condition. A rare but serious infection that may occur in these patients is Cryptococcus, an encapsulated fungus that typically infects immunocompromised individuals. Cryptococcus infections often present as pneumonia but can disseminate to the central nervous system, potentially causing meningitis. Therefore, Cryptococcus poses a significant threat and warrants prompt recognition and treatment. We present a case of a 75-year-old male being assessed for relapsed MM with extensive nodular mass-like opacities in the lungs on PET CT. A few months later, the patient presented to the emergency department with complaints of sudden onset abdominal pain, chills, and fatigue. A CT scan confirmed the presence of bilateral lung consolidations. It was subsequently established that the patient was likely experiencing a relapse of MM prompting adjustments to their treatment plan. Laboratory testing indicated that the patient's light chains and renal function improved with the altered therapy, but the patient had minimal improvement for the bilateral lung consolidations. One month later, the patient presented to the infusion visit with a cough and sore throat. Blood titers were positive for cryptococcal antigen, indicating a potential cause for the pulmonary infiltration. The team considered bronchoscopy or lung nodule biopsy to confirm the diagnosis; however, given the patient's frailty, they opted to monitor the clinical response and repeat a PET-CT scan in seven days. Additionally, cerebrospinal fluid analysis following a lumbar puncture was negative. The patient was started on oral fluconazole, leading to symptomatic improvement and resolution of pulmonary nodules on chest CT.