Eccrine angiomatous naevus revisited.

Hamartomatous, circumscribed swellings of the extremities make an interesting study. Presentations are manifold and the naevi are not always present from birth. Excessive growth of hairs leads to remarkable appearance of such swellings. A young woman presented to the dermatology department, complaining of tenderness over 4(th) finger of her left hand. The defect was present for the last couple of years and was typified by visible hyperhidrosis on gentle tapping. Counseling of the affected lady made her agree for a skin biopsy. The histopathology revealed it to be of the nature of eccrine angiomatous hamartoma. Blood vessels were scarce. Eccrine ducts were plentiful without other associated anomalies. The deformity was removed by simple excision with good result.

Introduction

Eccrine angiomatous hamartoma (EAH) is a benign enlargement of eccrine components, accompanied by abundance of vascular channels. Increased proliferation of pilar structures, adipose tissue, and epidermis may be present.[1] The anomaly is usually asymptomatic, but pain, hypertrichosis, and hyperhidrosis have been reported in a few patients. Less than 50 cases have been described in the literature. Recurrence is rare. Differentiation from other angiomatous growths is necessary.

Case Report

A 26-year-old female presented with a 2.5 cm × 1.5 cm blue-colored, ill-defined swelling over the dorsum of her left hand near the last intertriginous space encroaching over the ring finger. The surface was irregular in texture and she could demonstrate small beads of perspiration on patting the lesion [Figure 1]. This swelling was present for the last 2 years and she had sought medical aid as it was painful to touch. The adjoining skin over the 3rd metacarpophalangeal joint and proximal interphalangeal joint of the 3rd finger showed a skin-colored swelling and it represented an area of similar tumor which had grown slowly since birth. This earlier nevoid lesion had been excised 10 years back. Operated area was asymptomatic. There was neither suggestive family history nor any history of trauma to the part. Her blood reports were normal as was her chest radiograph. A 4 mm punch biopsy was performed and the histopathology revealed lobulated, unencapsulated structure composed of mature, numerous eccrine glands enmeshed in loose connective tissue [Figure 2]. Blood vessels could not be demonstrated with the eccrine coils in the specimen [Figure 3]. The person was sent to a surgeon and the hamartoma was completely removed. Eight months have passed without reappearance of the tumor.

Figure 1

Beads of perspiration on eccrine angiomatous hamartoma

Figure 2

Lobulated structures in the dermis showing eccrine glands (H and E, ×100)

Figure 3

Plentiful eccrine coils without blood vessels (H and E, ×400)

Discussion

Sebaceous naevi often contain eccrine element. Pure eccrine naevi are rare and usually accompanied by capillary angiomatosis. Such angioma was first described by Lotzbeck in 1859 and termed as EAH by Hymann and colleagues in 1968.[2] A case with familial disposition has been recorded in the literature. Clinically, the lesion presents as solitary, bluish, or skin-colored nodules or plaques usually over the extremities as trauma may be an inciting factor. Other areas like the trunk and face are known to be involved. Verrucous form has been reported. EAH can be multiple.[3] Numerous lesions in the same individual can be the result of mosaicism of a gene mutation occurring in the early developmental stage. Adult onset hamartoma has been described.[34] The tumor is painless, but involvement of nerve fibers by the enlarging eccrine elements can result in tenderness. Sudoriparous angiomas, as they are also known as, can display increased eccrine sweat production on exercise or when lightly stroked. Involvement of pilar structures by the malformation may manifest as hypertrichosis over the naevi.

Etiology of sudoriparous angiomas is unclear. It has been suggested that as yet an unclear chemical interaction between the differentiating epithelium and the mesenchyme leads to the abnormal proliferation of eccrine structures.[5] The tumor has to be differentiated from other structures like tufted angiomas, capillary hemangiomas, smooth muscle hamartomas, and dermatofibromas. Histopathology helps in confirmation of the diagnosis. Dilatation of eccrine coils is a constant feature with amplification in their numbers, but associated enlargement of vascular channels may not be present. This modification has been termed “naevus sudoriferous.”[6] Apart from closely entwined pilar structures and infiltration of adipose tissue, profuse deposition of mucin in the connective tissue has been detailed in the literature.[37] Seraly[8] et al. coined the term eccrine pilar angiomatous mucinous nevus for this variant of EAH.

Immunohistochemistry can give added and more specific information regarding the malformation. Carcinoembryonic antigen (CEA) and S-100 protein, which are commonly found in the eccrine sweat apparatus, are found to be diminished.[9] This investigation could not be performed in our case.

Malignant transformation has not been reported in such hamartomas. Spontaneous regression may occur. Simple surgical procedures like excision have produced excellent results where it was sought for pain or for cosmetic reasons. Lasers have not proved to be effective. Recurrences have not been known to occur.[10] Reason for reappearance in our case could be incomplete removal of the previous tumor. Associations of such eccrine hamartomas are not common. A case with Cowden's syndrome, who had developed a thyroid adenoma,[11] and another with neurofibromatosis[12] are the only two such reports.

EAH are rare malformations presenting diverse clinical and histological deviations which need differentiation from other complex tumors. They carry a good prognosis and treatment is simple, often providing complete gratification for the sufferer.