A large erythematous plaque of the scalp

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A 71-year-old male presented with a 2-year history of asymptomatic, well-demarcated papules and plaques localized to the vertex area of the scalp. The lesions appeared smooth, ranging in color from red to brownish, and were covered by branching vessels. Dermatoscopy revealed elongated linear and branching vessels distributed over a diffuse pinkish to orange background, which was nonspecific (Figure 1a, b). The medical history revealed arterial hypertension and hypercholesterolemia, both of which were being treated according to current guidelines, as well as a diagnosis of prostate cancer, which had been treated with radiotherapy and hormonal therapy twelve months prior to the onset of the lesions. The patient reported that several treatments had been attempted without substantial improvement in the case. First, topical mometasone had been tried for six weeks without any response. Following that, hydroxychloroquine at 200 mg twice a day and 0.1 % ointment of tacrolimus once a day had been given for six weeks, again with no response. He had then applied 0.05 % clobetasol ointment once a day for three months with no satisfactory improvement. A 5-mm punch biopsy was then performed, revealing dense nodular infiltrates composed of a mixture of lymphocytes, plasma cells, neutrophils, eosinophils, a few mast cells, and a large number of histiocytes, involving the entire dermis but sparing a thin band of the papillary dermis (grenz zone). The infiltrate displayed a peri-vascular, peri-adnexal, and interstitial distribution and was polymorphous in nature. In some foci, leukocytoclasia (nuclear neutrophilic dust), extravasated erythrocytes, hemosiderin deposits, and fibrinoid necrosis of small vessels were observed, consistent with features of leukocytoclastic vasculitis (Figure 2). The overlying epidermis was flattened but not atrophic and, although the papillary and reticular dermis showed a slight increase in collagenous fibrosis, the features of fibrosing vasculitis (considered the chronic form of leukocytoclastic vasculitis) were not detected. Your diagnosis? … Diagnosis: Extrafacial granuloma faciale Granuloma faciale (GF) is a rare benign idiopathic skin condition, primarily affecting middle-aged individuals. GF is characterized by a red-brown to violaceous plaque on the face, ranging in size from a few millimeters to several centimeters in diameter. It usually presents as a single lesion, although multiple lesions can also occur. As the name suggests, GF predominantly affects the face, with extrafacial involvement being uncommon.1 Although the etiology of GF is unknown, several studies have shown deposition of immunoglobulins and complement around blood vessels, suggesting an immune complex-mediated process contributing to vascular damage. This finding supports the hypothesis that GF may represent a localized variant of cutaneous small vessel vasculitis.1-3 While the face is the predominant site of involvement in GF, extrafacial locations, including the trunk and the upper extremities, have been reported.1-5 Mucosal involvement is exceptional, with cases of GF involving the penis and vulva documented in the literature. Compared to facial lesions, extrafacial lesions are more likely to be multiple, suggesting either distinct pathogenic mechanisms or varying local tissue responses. Among extrafacial sites, the exclusive scalp presentation of GF has been described in six cases (Table 1), all in male individuals (age 58–82 years), with an average age of 69.5 years.1, 6-9 A closer look at these cases reveals that most lesions were solitary, although multiple lesions were reported in three cases. Notably, all patients lacked facial involvement except one, and treatment strategies included topical and intralesional corticosteroids, tacrolimus, and pulsed dye laser, with varying degrees of success. The diversity in presentation and therapeutic response highlights the importance of considering GF in the differential diagnosis of atypical scalp lesions and the value of documenting additional cases to better understand this unusual localization. The manifestations of GF range from symptomatic lesions, such as itching and burning sensations, to asymptomatic ones. Diagnosing GF in extrafacial locations is challenging, particularly when facial lesions are absent. Histopathology is essential to confirm the diagnosis: the presence of a grenz zone, a mixed inflammatory infiltrate including histiocytes, eosinophils, and neutrophils arranged peri-vascularly, and subtle features of leukocytoclastic vasculitis (especially in the “early stage”). This interdisciplinary collaboration between the dermatologist and pathologist is crucial in difficult or atypical cases. In our patient, the diagnosis was supported by the combination of clinicopathologic correlation and the presence of classic histologic findings, which made additional ancillary techniques such as immunohistochemistry or direct immunofluorescence unnecessary. However, in more ambiguous presentations, these tools may be of diagnostic value, particularly when immune complex deposition or overlapping entities are suspected. Other granulomatous dermatoses to consider in the differential diagnosis include cutaneous sarcoidosis, cutaneous lymphoma, erythema elevatum diutinum, cutaneous lupus erythematosus, pseudolymphoma, and vasculitic disorders related to Churg-Strauss syndrome.1, 3 Misdiagnosis of GF is frequent, and these conditions may closely mimic its clinical appearance. However, histopathologic examination allows a reliable distinction. For instance, cutaneous sarcoidosis is characterized by noncaseating granulomas, in contrast to the mixed inflammatory infiltrate seen in GF. Cutaneous lymphomas and pseudolymphomas present histologically with atypical or dense lymphoid infiltrates, while GF typically exhibits a polymorphous infiltrate rich in eosinophils. Cutaneous lupus erythematosus shows a predominantly lymphocytic infiltrate with epidermal involvement, features absent in GF. Erythema elevatum diutinum may resemble GF both clinically and histologically but usually involves the extremities and shows specific findings such as superficial scar-like fibrosis and clefts within fibrotic tissue. Several reports suggest that environmental triggers or comorbid conditions such as rheumatoid arthritis and Sjögren's disease may play a role in the development of GF, highlighting the importance of long-term follow-up in these patients.10 Granuloma faciale is a chronic and recidivistic condition, with many cases relapsing despite therapy, and, if untreated, it generally persists indefinitely in the absence of spontaneous resolution. Various therapies for GF exist, most with unsatisfactory results in extrafacial lesions. Anti-inflammatory topical corticosteroids include the following: 0.05 % clobetasol propionate and 0.1 % mometasone. Regarding topical steroid-sparing agents, 0.1 % tacrolimus ointment has been suggested as being of particular value for maintenance in such cases. Intralesional corticosteroids are generally used, at times in combination with cryotherapy or systemic agents such as dapsone 50–100 mg daily or hydroxychloroquine. Pulsed dye laser (PDL) and cryotherapy represent procedural treatments directed toward vascular or localized components of the lesions. Surgical excision is seldom carried out but may be attempted in resistant cases. Overall, treatment outcomes are disappointing, with a high recurrence rate, thus underlining the need for new therapies and standardization of treatment approaches. A personalized approach, especially in cases with extensive or symptomatic extrafacial lesions, is paramount in addressing the needs and preferences of the patients.6-9 Although direct evidence is currently lacking, topical ruxolitinib, a selective JAK1/2 inhibitor, may represent a potential future therapeutic option for granuloma faciale. Its efficacy in other chronic inflammatory conditions and vitiligo sugges

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