INTRODUCTION
An African-American female, aged 27 years, presented to
the dermatology clinic for a follow-up evaluation of multiple
pruritic, darkly pigmented papules on the face, ears,
chest, abdomen, back, upper extremities, and lower extremities.
She was referred from the gastroenterology clinic where she was
receiving treatment for primary sclerosing cholangitis (PSC).
The patient had been seen approximately eight months previously
by dermatology as an in-patient consult for this same complaint.
At that time, the patient was admitted to the hospital for acute pancreatitis,
cholecystitis, and eosinophilia due to underlying PSC. A
shave biopsy of one of the characteristic skin lesions was read as
lichen spinulosis. Phyrynoderma was also entertained due to a
low serum level of vitamin A (15 µg per dL). After a cholecystectomy,
the patient was discharged from the hospital on a treatment
regimen of ursodiol, lansoprazole, vitamin A supplementation,
topical keratolytics, and oral antihistamines.
When the patient was seen several months later, her physical
exam revealed over 100, 1 mm to 8mm hyperpigmented, round,
perifollicular, and parafollicular papules with some coalescence
into plaques. Many papules contained a central keratotic plug.
The lesions were most prominent on the extensor surfaces of
the legs, but also on the arms, chest, back, abdomen, and a few
lesions on the face and ears (Figures 1 and 2). There was no involvement
of the palms, soles, or mucous membranes. Icterus
of the sclera and of the oral mucosa, especially the sublingual
mucosa, was noted. Besides a personal history of PSC, past
medical history and family history were non-contributory.
Punch biopsies were taken from two separate lesions on her bilateral
lower extremities. The histology of a papule on the right
thigh showed a dilated follicular infundibulum with a central
keratotic plug. The papule on the left thigh revealed a transepithelial
channel lined by an acanthotic and hyperkeratotic
epidermis with degenerated follicular contents, elastin, collagen
and a granulomatous reaction at the base (Figures 3 and 4). Her
clinical lesion distribution, known medical history of PSC, lack of
improvement with vitamin A supplementation, and histological
analysis favored the diagnosis of a perforating dermatosis.
DISCUSSION
The disorders of perforation are unique as they represent examples
of transepithelial elimination in which altered dermal
substances are extruded through epidermal channels. The 4
classically described perforating disorders include elastosis
perforans serpiginosa (EPS), reactive perforating collagenosis
(RPC), perforating folliculitis (PF), and Kyrle's disease
(KD). In EPS, the extruded substance is elastin. In RPC, the
substance is collagen. In PF, it is degenerated follicular contents,
which may contain elastic fibers or collagen. Lastly,
in KD, the substance is basophilic debris, which is generally
negative for elastic stains.1
