[Nail abnormalities revealing AL systemic amyloidosis].

BACKGROUND

Mucocutaneous involvement in systemic amyloidosis occurs in 29 to 40%. Purpura and macroglossia are the most frequently signs. Nail involvement is rarely observed. We reported a case of systemic amyloidosis AL revealed by nail abnormalities.

METHODS

A 76-year-old-man consulted for nail lesions lasting for several months with subungual hyperkeratosis, distal onycholysis and subungual splinter hemorrhages. The remainder of the dermatological examination highlighted a faint purpuric erythema of eyelid that was overlooked. Further diagnostic work-up confirmed the diagnosis of systemic amyloidosis associated with multiple myeloma lambda light chains.

CONCLUSIONS

Nail abnormalities in systemic amyloidosis AL are rarely described. They can take many forms and can sometimes be the only cutaneous manifestation of systemic amyloidosis. Skin biopsy of the nail matrix can confirm the diagnosis with a potential risk of sequela onychodystrophy nail. Labial salivary gland biopsy seems to be the most sensitive method for diagnosing systemic amyloidosis.