The histopathology of closed and open comedones of Favre-Racouchot disease.
OBJECTIVE
To determine the distinction between a comedo and an infundibular cyst of Favre-Racouchot disease.


METHODS
A university hospital.


METHODS
From the 8 patients included in the study, 19 cysts and comedones were evaluated.


METHODS
The distinguishing features between the cysts and comedones of Favre-Racouchot disease.


RESULTS
All lesions were histologically indistinguishable from the primary comedones of acne vulgaris, except for the presence of a marked actinic elastosis in the surrounding dermis. The presence of a variable number of hair shafts and an abundant amount of bacteria, which was positive in the results of Gram staining and periodic acid-Schiff reaction and intermingled with sebum and eosinophilic laminated horny material within the dilated infundibulum, characterizes a comedo and differentiates it from an infundibular cyst.


CONCLUSIONS
The cysts and comedones of Favre-Racouchot disease are closed and open comedones. They can be easily differentiated from an infundibular cyst by the histopathologic features rather than by the connection to the surface.
Sánchez-Yus
E
E
Department of Dermatology, Hospital Universitario San Carlos, Madrid, Spain.
del Río
E
E
Simón
P
P
Requena
L
L
Vázquez
H
H
D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005148:Facial Dermatoses / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged