Localized Cutaneous Amyloidosis Secondary to Porokeratosis: A Retrospective Histopathologic Study of 30 Patients

IntroductionPorokeratosis is a rare disorder of keratinization. The presence of amyloid deposits has been observed in inflammatory and tumoral skin diseases.ObjectivesThe aim of this study was to determine the frequency of cutaneous amyloidosis in histology samples from various types of porokeratosis diagnosed in our department from 1988 to 2005.Material and methodsThirty patients were selected and 34 biopsies of lesions clinically and histologically compatible with porokeratosis were performed. Sections were stained with hematoxylin-eosin and thioflavin T.ResultsAmyloid deposits were observed in 11 biopsies from 9 patients. Most were women in their sixties, with disseminated superficial actinic porokeratosis that had begun at least 5 years earlier. No notable histologic differences were observed between porokeratosis specimens with and without amyloid deposits.ConclusionsThe coexistence of porokeratosis and amyloidosis is a rare occurrence but may be underdiagnosed. In our opinion, the advanced age of the patients and the chronic nature of the lesions would have been predisposing factors for amyloid deposition. The possibility of racial or genetic influences, however, cannot be ruled out.

ResumenIntroducciónLas poroqueratosis son alteraciones de la queratinización poco frecuentes. La presencia de material amiloide se ha observado en dermatosis de etiología inflamatoria y tumoral.ObjetivosDeterminar la incidencia de amiloidosis cutánea en las muestras histológicas de distintos tipos de poroqueratosis diagnosticados en nuestro servicio entre 1988-2005.Material y métodosSe seleccionaron 30 pacientes y se realizaron 34 biopsias de lesiones compatibles clínica e histológicamente con poroqueratosis. Se realizaron tinciones con hematoxilina-eosina y tioflavina T en todas ellas.ResultadosSe detectaron depósitos de amiloide en 11 biopsias que pertenecían a 9 pacientes. La mayoría eran mujeres en la sexta década de la vida, con la variante de poroqueratosis actínica superficial diseminada y con un tiempo de evolución superior a 5 años. No se encontraron diferencias histológicas significativas entre las biopsias de poroqueratosis con amiloide y sin él, a excepción del material anómalo.ConclusionesLa coexistencia de poroqueratosis y amiloidosis es un hecho poco frecuente, posiblemente infradiagnosticado. Consideramos que la edad avanzada y la cronicidad de las lesiones serían factores predisponentes, sin poder descartarse una implicación racial o genética.