Grouped Inflamed and Umbilicated Papules: A Distinct Clinical Presentation of Perforating Sarcoidosis

Dear Editor,

A 56-year-old nondiabetic, nonhypertensive man presented with multiple itchy lesions on the trunk, upper limbs, and lower limbs (face spared) for eight years. There was no history of cough, breathlessness, redness of eyes, or photophobia. On examination, there were multiple grouped erythematous to yellowish-red flat-topped round to polygonal papules, with surrounding prominent erythema present on the above-mentioned sites. Many of the papules had central crusted umbilication. Similar lesions were observed on the legs and thighs. [Figure 1a and b] The differential diagnoses of perforating sarcoidosis and perforating granuloma annulare were considered. Dermoscopic examination (Heine Delta 20T, 10X) showed yellow to yellowish-white structureless areas, brown dots, globules, and structureless areas, rosette, shiny white structureless areas, linear irregular, hairpin and linear vessels with branches [Figure 2a]. Systemic examination was normal. Punch biopsies for histopathology were performed from two lesions, one smooth papule and one with a central crust, revealing an atrophic epidermis with coalescent epithelioid cell granulomas in the upper dermis with occasional giant cells and minimal lymphocyte cuff around granulomas [Figure 2b]. Special stains, including periodic acid–Schiff, acid fast bacilli, and Fite-Faraco, were negative. Blood investigations, including complete blood count, liver function test, kidney function test, and urine routine and microscopy, were within normal limits. Further workup to assess for systemic involvement, such as chest X-ray, high-resolution computer tomography, serum angiotensin convertase enzyme levels, and serum calcium levels, was noncontributory. Ophthalmology and pulmonology review did not reveal any abnormality. A diagnosis of cutaneous perforating sarcoidosis of papular type was made, and the patient was started on hydroxychloroquine 200 mg twice daily in view of diffuse skin involvement.

Figure 1.

(a) Clinical image of the right thigh shows multiple grouped erythematous to yellowish-red flat-topped round to polygonal papules, with surrounding prominent erythema. (b) Close-up view better visualizes the central crusted umbilication and surrounding erythema

Figure 2.

(a) Dermoscopy shows yellow to yellowish-white structureless areas, brown dots, globules, and structureless areas, rosette, shiny white structureless areas, linear irregular, hairpin and linear vessels with branches (Heine Delta 20T, 10X). (b) Histopathology shows grossly atrophic epidermis, coalescent epithelioid cell granulomas in the upper dermis with giant cells and minimal lymphocyte cuffing around granulomas. Note the granuloma indenting the epidermis (H and E stain, X400)

Sarcoidosis is an inflammatory multisystemic granulomatous disease commonly affecting the lungs, lymph nodes, eyes, and skin. It is a great imitator and clinically can present with either specific (showing sarcoidal granulomas on histopathology) or nonspecific lesions, including erythema nodosum. Various clinical presentations of specific lesions include maculopapules, plaques, lupus pernio, scar, and subcutaneous sarcoidosis. The classical histopathology includes noncaseating epithelioid granulomas in the dermis with a pauci-lymphocyte cover.[1]

The concept of transepithelial elimination (TEE) was first introduced in 1968 (Mehregan, Mehregan and Coskey). While analyzing the histopathology of elastosis perforans serpiginosa and perforating folliculitis, the authors noticed that the inflammatory cell infiltrate and abnormal dermal fibers were being eliminated through perforating channels formed within the epidermis and the follicular epithelium.[1] The pathogenesis involves a sequence of events starting with binding of foreign or altered material to an unidentified receptor which incites a dermal reaction, further leading to epidermal hyperplasia and formation of transepidermal perforating channels through which foreign substances are moved outward. Recently, a receptor for advanced glycation end products has been proposed to contribute in the pathogenesis of acquired perforating collagenosis by regulating collagen–keratinocyte interaction and migration. Disorders of TEE can be either classical (elastosis perforans serpiginosa, reactive perforating collagenosis, perforating folliculitis, and acquired perforating disorders) or nonspecific disorders, only showing TEE on histopathology.[2] Multiple granulomatous infective and noninfective conditions have displayed transepithelial elimination, including perforating granuloma annulare, necrobiosis lipoidica, rheumatoid nodule, cutaneous tuberculosis, lobomycosis, and chromoblastomycosis. Cutaneous sarcoidosis with TEE has also been reported in the literature with papular, plaque, and psoriasiform subtypes.[3] A retrospective series by Ismail et al.[4] has reported TEE in nine out of 50 cases of cutaneous sarcoidosis, possibly a common but missed finding.

Cutaneous sarcoidosis is known to be non-inflammatory; however, the present case was associated with significant itching and erythema around the lesion, which the reaction to TEE can possibly explain. The finding of TEE in all diseases known to have this finding has been seen with inflammation and/or granulomas in the upper dermis close to the dermo-epidermal junction.[4] A case with a similar presentation to the present case, papules with keratotic plugs, and TEE on histopathology has been reported.[5] The mechanism of TEE is still unknown in sarcoidosis. It’s significance in relation to clinical subtype and disease prognosis is unknown and requires further research. In our case, the patient had no extracutaneous manifestation despite the disease being present for eight years.

In conclusion, we report a rare case of perforating sarcoidosis, presenting as grouped umbilicated and crusted papules in a patient without extracutaneous manifestation. This morphology should prompt clinicians to consider sarcoidosis as a differential diagnosis despite its inflammatory nature.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.