Fox fordyce disease = داء فوكس فوردايس |
|
|
|
Fox Fordyce Disease
Fox-Fordyce disease (apocrine miliaria) is a disorder of apocrine sweat glands characterized by firm, itchy, follicular papules in anatomic sites where apocrine glands occur, namely the axillae , areolae, and genitalia . It occurs almost exclusively in women after adolescence.
|
Histopathology.
Step sections of a vertically oriented biopsy specimen are usually needed adequately to show the characteristic changes. There is hyperkeratosis of the follicular infundibulum and excretory duct of the apocrine sweat gland at the point where the latter inserts into the hair follicle. The apocrine duct behind the obstructing keratin plug becomes dilated . A spongiotic vesicle occurs in the follicular infundibulum, possibly representing an apocrine sweat-retention vesicle, with potential to rupture. Lymphocyte exocytosis is seen in the area of spongiosis. There may also be infundibular acanthosis and mild perivascular and periadnexal lymphocytic inflammation in the adjacent upper dermis . A comprehensive review of the histopathology noted other possible microscopic findings, including vacuolar alteration at the dermoepithelial junction of infundibula, dyskeratotic cells in infundibula, cornoid lamella-like parakeratosis within an orthokeratotic plug filling a dilated infundibulum, and foamy macrophages surrounding follicular infundibula and apocrine ducts . Transverse histologic sections facilitated identification of the diagnostic histologic features in one case, and this technique was touted as the most effective way to diagnose Fox-Fordyce disease on biopsy .
|
A third type of sweat gland has been identified in the axillae; it is intermediate in size between the larger apocrine gland and smaller eccrine gland . Called the apoeccrine gland, it has a secretory coil like an apocrine gland
|
but opens directly to the epidermal surface like an eccrine gland. A recent article details a case of Fox-Fordyce disease characterized by nonfollicular papules that histologically showed blockage of the intraepidermal portion of the apoeccrine sweat duct by cells that were released from the secretory portion via a holocrine mechanism .
Pathogenesis.
The pathogenesis appears to be related to blockage of the apocrine sweat duct. Apocrine anhidrosis results, as demonstrated by the lack of apocrine secretion following intradermal injections of an epinephrine solution into the affected area . There are, however, reports suggesting that mechanical obstruction alone may not explain Fox-Fordyce disease .
|
|