Papular sarcoidosis of the knees: a clue for the diagnosis of erythema nodosum-associated sarcoidosis.
BACKGROUND
In recent years we have systematically explored the skin whenever sarcoidosis was suggested and we have observed with increasing frequency the presence of granulomatous cutaneous lesions of sarcoidosis involving the knees.


OBJECTIVE
We sought to evaluate the specific cutaneous lesions of sarcoidosis involving the knees.


METHODS
A total of 18 patients with biopsy-proven specific cutaneous sarcoidosis predominantly involving the knees were included in the study. Biopsy specimens were evaluated under polarized light.


RESULTS
Of these cases, 4 corresponded to scar-sarcoidosis, 1 to plaque-type sarcoidosis, and 13 were an admixture of papules and minute scars frequently associated with erythema nodosum (papular sarcoidosis of the knees). Foreign particles were observed in 10 of 13 patients with papular sarcoidosis.


CONCLUSIONS
Papular sarcoidosis of the knees can be considered a frequent form of cutaneous sarcoidosis, mainly observed in acute forms of the disease, and frequently associated with erythema nodosum.
Marcoval
Joaquim
J
Department of Dermatology, Pathology, Hospital de Bellvitge, University of Barcelona, Spain. jmarcoval@csub.scs.es
Moreno
Abelardo
A
Mañá
Juan
J
D004893:Erythema Nodosum / Q000150:complications*; D005547:Foreign Bodies; D006801:Humans; D007717:Knee; D012507:Sarcoidosis / Q000150:complications / Q000175:diagnosis*; D012871:Skin Diseases / Q000150:complications / Q000175:diagnosis*