A man in his 60s presented with severe fatigue. His medical history was significant for primary hyperparathyroidism 6 years prior to presentation, for which the patient refused therapeutic management. The patient was cachectic and exhibited significant muscular weakness. Clinical examination revealed a large tumor on the distal part of the right fourth finger (Figure, A) that had gradually enlarged in recent months. Radiography revealed complete lysis of the underlying phalanx and periosteal bone resorption in the phalangeal tuft band.