BH10 Nailing the diagnosis

Abstract We present the case of a 60-year-old man, who was seen as an inpatient consult with regards to nail changes and lesions on the palmar surfaces of his hands. His background was significant for a malignant melanoma excised from his left pinna 8 months prior, type II diabetes mellitus, and bilateral carpal tunnel syndrome. He had last been seen in the dermatology service 3 months prior, as part of his routine melanoma surveillance. He was noted at this time to have koilonychia, with some longitudinal fissuring on all fingernails on his left hand and on the thumb and index finger of his right hand. He advised that this had been going on for a number of months, and his toenails were noted to be normal. He denied any trauma or contact with any solvents to his nails. His only new medication in the preceding months was semaglutide, which had been commenced approximately 4 months prior to review. Blood tests including iron studies and thyroid function tests were normal, and it was postulated that the symptoms might be related to his diabetes mellitus. He was subsequently admitted to hospital with worsening shortness of breath, and he was noted to have a pleural effusion. An echocardiogram demonstrated a reduced ejection fraction of 40–45%, and the appearance was suggestive of an infiltrative pathology, raising the possibility of amyloidosis. On review of his bloods, renal function was preserved. When he was seen as an inpatient consult, he now had koilonychia and longitudinal fissuring on all fingernails and toenails, and he had developed firm, pale subcutaneous papules on the palmar aspects of his hands and fingers. These were nontender on exam. A biopsy was performed of a papule on his right index finger, and this demonstrated mild hyperkeratosis, mild epidermal hyperplasia and mild chronic inflammation. A Congo red stain was performed, showing apple-green birefringence, confirming a diagnosis of amyloidosis. Subsequent cardiac magnetic resonance imaging confirmed a diagnosis of advanced cardiac amyloidosis, and subtype analysis is pending. In terms of the nail pathology, the hypothesis is that amyloid infiltration of the nail causes brittleness, longitudinal ridging and crumbling; patients may report having soft or thin nails. This patient had further cutaneous findings of systemic amyloid, with haemorrhagic bullae secondary to enoxaparin administration evident on his abdomen. This case highlights that it is worth considering amyloid in one’s differential diagnosis when patients present with nail findings such as described above, and assessing for other organ involvement.