Underneath the "apple-jelly".

The patient

A 44-year-old Caucasian woman presented with asymptomatic skin lesions on the trunk, arms and legs. These lesions had suddenly appeared 4 months before and have been unchanged ever since. Medical history included arterial hypertension and hypertriglyceridemia. The patient recalled an acute episode of painful subcutaneous nodules on the lower legs some years ago that disappeared with NSAID and leg rest.

On physical examination, we observed a bilateral and symmetric dermatosis composed of multiple well-defined erythematous papules and plaques involving the trunk, arms and legs, and sparing the face, acral sites and mucosae. Some of the papules appeared to be pseudovesicular with a yellowish hue (Figure 1).

Figure 1.

Disseminated papules and plaques on the trunk, arms and legs. [Copyright: ©2016 Mendes-Bastos et al.]

Further dermoscopic examination disclosed multiple orange and yellowish globules and structureless areas in combination with linear vessels (Figure 2).

Figure 2.

Multiple orange-yellowish structureless areas (surrounded by asterisks) and linear vessels in a yellow-tone background. [Copyright: ©2016 Mendes-Bastos et al.]

A 4 mm punch biopsy was performed. Histopathological examination revealed an unchanged epidermis and organized collections of epithelioid histiocytes on the superficial and deep dermis (Figures 3 and 4).

Figure 3.

Unchanged epidermis and a dermal granulomatous dermatitis. [Copyright: ©2016 Mendes-Bastos et al.]

Figure 4.

Organized collections of epithelioid histiocytes on the superficial and deep dermis, with scattered multinucleated giant cells. [Copyright: ©2016 Mendes-Bastos et al.]

No necrosis or other inflammatory infiltrate were observed. Periodic acid-Schiff (PAS), Grocott and Ziehl-Neelsen stains were unremarkable.

What is your diagnosis?

Diagnosis

Cutaneous sarcoidosis

Clinical course

Chest CT revealed bilateral hilar lymphadenopathy. The patient was referred to pulmonology, and Stage I sarcoidosis was diagnosed.

Answer and explanation

Sarcoidosis is an idiopathic multisystemic granulomatous disease that mostly involves the lung, lymph nodes, eyes and skin. Cutaneous involvement is seen in 25% of patients. Specific skin lesions of sarcoidosis are highly polymorphous and establishing a correct diagnosis is frequently a challenge [1]. In this particular case, the clinical differential diagnoses included secondary syphilis, eruptive xanthomas and cutaneous lymphoma.

The term inflammoscopy has been introduced to describe the use of dermoscopy in the diagnosis of inflammatory skin diseases [2]. The combination of orange and yellow translucent globules and linear vessels is commonly seen under dermoscopy in granulomatous diseases. These structures correlate well with the underlying dermal granulomas. Thus, they are frequently found in cutaneous sarcoidosis and lupus vulgaris, probably mirroring the classically described “apple-jelly” sign observed upon diascopy. Therefore, under appropriate clinical correlation, dermoscopy can be a valuable non-invasive tool for the diagnosis of cutaneous sarcoidosis [3].