Reactive eccrine syringofibroadenoma in hyperkeratotic eczema.

Sir,

Eccrine syringofibroadenoma (ESFA) usually presents as a solitary, large hyperkeratotic nodule affecting the extremities. It is a benign neoplasm with eccrine duct differentiation with several rare associations and clinical variants. It also occurs as a reactive process with various dermatoses.[1] We report a case of reactive ESFA occurring in a hyperkeratotic palmar and plantar eczema.

A 50-year-old woman presented with severely itchy lesions on her palms and soles since 2–3 months. On enquiry, she revealed that lesions were extremely itchy and were growing in size since it started. There were no similar lesions elsewhere on her body. Family history of similar lesions was negative. On examination there were well-defined thick scaly erythematous plaques predominantly involving the heels and lateral aspect of both her feet. Similar plaques were also present on both palms. Such lesions were not present on any other part of the body. Scalp and nails were spared [Figures 1 and 2]. A differential diagnosis of chronic lichenified eczema or psoriasis was kept. Routine blood investigations were normal. Serum IgE level was markedly raised [828 Ku/L normal range, 0–114] suggesting allergic etiology.

Figure 1

Erythematous thick scaly well-defined plaque over lateral border and heel of right foot

Figure 2

Closeup view of the lesion

Biopsy from the lesion showed features of hyperkeratosis with epidermal hyperplasia and thin cords of epithelium progressing downward, anastomosing with each other to form a net-like pattern embedded within a fibrovascular stroma with eccrine ducts at several places. Overlying epidermis showed moderate spongiosis. Dermal infiltrate comprised of superficial perivascular lymphohistiocytic infiltrate with few eosinophils. With these findings we reached a final diagnosis of reactive syringofibroadenoma in hyperkeratotic palmo-plantar eczema [Figures 3 and 4]. The patient was treated with oral sedative anti-histaminics along with topical high-potent steroids and keratolytic agents.

Figure 3

Hyperkeratosis with epidermal hyperplasia and spongiosis of overlying epidermis with lattice of epithelial cords progressing downward and interconnecting. (H and E ×4)

Figure 4

Fibrovascular stroma with eccrine ductal hyperplasia and few eosinophils. (H and E ×40)

ESFA as described by Mascaro in 1963, is a rare benign neoplasm with eccrine differentiation.[12] Starink[2] proposed a classification comprising four subtypes, namely, (1) Solitary ESFA, a nonhereditary verrucous tumor in elderly individuals; (2) Multiple ESFA without other cutaneous findings; (3) Multiple ESFA with hidrotic ectodermal dysplasia (Schopf syndrome); (4) Nonfamilial unilateral linear ESFA probably represent a genetic mosaic caused by a postsomatic mutation.

Apart from these, another clinical type has been suggested by French,[2] which has been named as “Reactive ESFA,” associated with inflammatory or neoplastic disorders such as lichen planus, bullous pemphigoid, burn scar, pincer nail, ileostomy stoma, diabetic foot ulcer, leprosy,[3] plantar hyperkeratosis,[4] mossy foot, and squamous cell carcinoma. Our case can be categorized in this category, with its associated eczema.

Histopathology of ESFA mimics premalignant fibroepithelioma of pinkus,[2] classically it reveals a lattice of thin epithelial cords interconnected to the undersurface of the epidermis. The cells are smaller and more basaloid than the overlying epidermal keratinocytes. Ducts are present within the tumor and between the strands there is a rich fibrovascular stroma. In addition to these findings our case showed features of allergic etiology both serologically, which was evident by high IgE levels and on biopsy by spongiosis of overlying epidermis and eosinophils in the dermal infiltrate.

Mehregan[2] pointed out that eccrine duct proliferation can occur as a reactive process in various inflammatory and neoplastic conditions. Therefore, cases showing lesions of reactive ESFA may be a result of repeated tissue damage and repair caused by the underlying “primary” inflammatory or neoplastic condition. Intense bouts of itching relieved with vigorous scratching with all sorts of articles such as comb, pebbles, and others may have resulted in eccrine duct damage and reactive hyperplasia in our case. However, why such a change does not occur in all cases of eczema probably points out to genetic predisposition.

Treatment of solitary ESFA comprises of complete excision as malignant transformation has been reported.[3] However, this approach is impractical in larger plaque-type lesions as in our case, wherein treatment of primary condition along with close observation through regular follow-ups is more feasible.

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Conflicts of interest

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