Neurovisceral Syndrome in a Patient with Monoclonal Gammopathy of Undetermined Significance: A Confirmed Case of Variegate Porphyria

Variegate porphyria (VP) is a rare disorder presenting with cutaneous, neurological, and systemic symptoms. We report a 53-year-old man initially hospitalized for a depressive episode, during which blistering lesions and facial flushing were noted. He was misdiagnosed and treated for cellulitis and contact dermatitis without improvement. Repeated misdiagnoses led to extensive autoimmune, infectious, and hematologic workup, revealing coexisting monoclonal gammopathy of undetermined significance (MGUS). Over the following months, he developed abdominal pain, mood swings, cognitive impairment, neuropathy, orthostatic symptoms, and weight loss, raising suspicion for porphyria. A 24-hour urine panel revealed elevated porphobilinogen (PBG), delta-aminolevulinic acid (ALA), coproporphyrin I and III, heptacarboxyl porphyrins, and mildly elevated uroporphyrins, confirming VP. Treatment with hemin caused thrombophlebitis and was discontinued. He was transitioned to Givosiran, resulting in symptom control and no further flares. This case reinforces the need to consider rare metabolic disorders in unexplained multisystem presentations and highlights the role of enzyme-targeting therapy when conventional treatment is not tolerated.