Pyoderma fistulans sinifica (pyodermia fistulans sinifica, PFS) is a rare chronic disorder with multiple, complex fistulas and sinus tracts.


The disorder is referred to as “fox den disease” because the fistulae are long and complex. The complexity of the fistulas can make clinical management challenging.


The condition is felt by some authors to be the same as Hurley Stage 2 or 3 hidradenitis suppurativa (HS).


Other authors (Wittmann et al) note the following differences from HS:

(1) lining by stratified squamous cell epithelium

(2) no relationship to skin appendages

(3) course deep into the subcutaneous tissue

(4) epifascial course for fistulas


The fistulas may affect:

(1) perianal region

(2) inguinal region

(3) axilla



(1) elephantiasis of the scrotum (megascrotum)

(2) systemic inflammatory response which can lead to organ failures


Wittmann et al recommend wide en-bloc excision down to the fascia with removal of all fistulae.


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