A rare case of vulvar sarcoidosis highlights the value of biopsy when presumed lichen sclerosus is persistent, atypical, or fails to respond as expected.
Dermatologists should consider sarcoidosis in the differential diagnosis of persistent or atypical vulvar pallor, Australian clinicians say.
They have documented what they say appears to be only the second reported case of external genital sarcoidosis mimicking lichen sclerosus.
The case, published in the Australasian Journal of Dermatology, involved a 69-year-old woman with a 40-year history of persistent vulvar pruritus and pallor and atrophy affecting the right labia minora and clitoris.
Her symptoms had first appeared postpartum and had been treated intermittently with topical corticosteroids, with variable response. More consistent use of higher-potency topical corticosteroids and vulvar hygiene measures had improved her symptoms.
The woman also had biopsy-confirmed cutaneous sarcoidosis involving her knee, posterior neck, and mons pubis, while a pulmonary lesion had been detected radiologically and was under respiratory review.
On examination, clinicians found orange-red annular plaques on the neck and knee and orange-brown plaques on the mons pubis and labia majora. But the right labia minora and clitoris had pallor and atrophy consistent with lichen sclerosus, accompanied by an interlabial sulcus fissure.
A punch biopsy of the pale area changed the picture.
Histopathology showed granulomatous dermatitis with well-formed epithelioid granulomas and multinucleated giant cells. There was no necrosis, suppuration, or foreign-body reaction, and special stains were negative for fungal and mycobacterial organisms. Crucially, the biopsy showed no features of lichen sclerosus.
Clinicopathological correlation supported a diagnosis of vulvar sarcoidosis mimicking lichen sclerosus in the setting of systemic cutaneous sarcoidosis. The patient was treated with nightly mometasone furoate 0.1% ointment, which was subsequently tapered, alongside ongoing vulvar skincare measures.
The researchers said external genital cutaneous sarcoidosis was uncommon and could have a wide range of appearances.
Their literature review identified just one previous genital case mimicking lichen sclerosus after overlapping reports of the same patient were de-duplicated. The new case therefore appeared to be the second documented external genital lichen sclerosus mimic.
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They said several clinical clues should raise suspicion and prompt biopsy, including asymmetrical disease, labia minora or clitoral predominance, papules or nodules within an area of pallor, induration inconsistent with lichen sclerosus, persistent or relapsing disease, and a poor or incomplete response to an adequate course of ultra-potent topical corticosteroid.
A history of sarcoidosis, other cutaneous sarcoid lesions, respiratory symptoms, or lymphadenopathy may provide further clues.
While the two diseases could look alike, the researchers said that the available literature did not establish a causal relationship between sarcoidosis and lichen sclerosus.
Instead, they proposed that the overlap may reflect the tendency of sarcoidosis to localise in altered or chronically inflamed skin, occasionally producing white atrophic vulvar lesions resembling lichen sclerosus.
“For atypical or steroid-refractory white plaque disease on external genitalia, biopsy should be prioritised,” they concluded.
“Systemic staging should be performed once non-caseating granulomas are confirmed.
“Management of localised cases involves high-potency topical corticosteroids, with calcineurin inhibitors used as maintenance therapy. Systemic agents are reserved for multisite or systemic disease.”
