Correspondence Address:
Pragya Ashok Nair
Department of Dermatology & Venereology, Pramukhswami Medical College, Bhai Kaka University, Karamsad 388325, Gujarat
India

Full Text



Dear Editor,

A 60-year old lady presented to the skin outpatient department with a 1.5 year- old complaint of a slow growing lesion over neck, associated with occasional bleeding and mild burning sensation. There was no difficulty in swallowing or any other systemic complaint. She was hypertensive since 15 years. Cutaneous examination revealed multiple erythematous papules coalescing to form 3 plaques of size varying from approximately 0.5 to 2 cm, with telangiectasia, erosions covered with crusting and collarette scale at the margin, over midline of neck [Figure 1]. On palpation, the lesions were non-tender and firm to touch. No cervical or occipital lymphadenopathy was present. Her baseline investigations, hemogram, liver and renal function tests, serum electrolytes and urine examination were within normal limits. We examined the lesion with a DE-300 polarizing digital dermatoscope (Firefly) having 20x magnification which revealed hairpin and linear vessels arranged irregularly [Figure 2]A. One of the lesions also showed linear vessels with surrounding collarette scale as well as a white-to-pink halo [[Figure 2]B].{Figure 1} {Figure 2}

Based on history, cutaneous examination and dermatoscopy we considered pyogenic granuloma, eccrine poroma, haemangioma, basal cell carcinoma and porocarcinoma as differentials. A biopsy was taken which showed a benign adnexal tumour with focal eccrine differentiation, emanating from the lower portion of the epidermis in the form of large diffuse sheets of small basaloid epithelial cells having a uniform cuboidal appearance, a round, deeply basophilic nucleus and minimal cytoplasm [[Figure 3]A]. The tumor cells focally showed cytoplasmic vacuolation and narrow ductal lumina with cystic spaces [[Figure 3]B]. Diagnosis of eccrine poroma was made. She was treated with cryotherapy for 2 months, but lesions did not subside. Finally, the poroma was completely excised under local anesthesia with good aesthetic outcome and without any recurrence.{Figure 3}

Poromas are a subset of benign adnexal neoplasms, involving terminal intra epidermal portion of sweat gland duct known as the acrosyringium with proliferation of poroid cells, which form around 10% of sweat gland tumors[1] with eccrine or apocrine etiology. It commonly affects the middle age to elderly population and does not have a predilection for race or sex.

Clinically it appears as a single slow growing, symptomless, soft, well-circumscribed papule, plaque or nodule which is pink-to-red in color with a smooth to verrucous, occasionally ulcerated surface. Multiple lesions, pigmented variants and unusual sites of localization such as head and neck may also occur,[2] like the multiple plaques of eccrine poroma over neck in our case. Other clinical features include an indented moat with collarette scale surrounding the lesion and a tendency to bleed with minor trauma which was also seen in our case.[3]

About two-third of cases are seen on soles or sides of soles followed by hands and fingers due to high density of sweat glands and rarely over the head, neck and trunk.[2],[4] An important tool for diagnosis of eccrine poroma is dermoscopy, a fast evolving field which has enhanced the diagnostic accuracy for many cutaneous conditions due to its non-invasive nature, image magnification and polarized imaging. The most prominent dermatoscopic finding in eccrine poroma is the characteristic vascular pattern which can be polymorphic, glomerular, linear-irregular, looped, hairpin or leaf and flower-like; the latter being relatively unique to poroma.[5] Ferrari et al. showed a white to pink halo and pink white structureless areas, thought to be due to fibrinoid edema surrounding dilated vessels of the tumor and dermal lamellar fibroplasias respectively.[2] The presence of vascular blush secondary to the vasodilatation and high vascular volume of these tumors, as well as interlacing white cords, are also quite specific to the poroma.[5] These findings corresponded with those in our case which showed hairpin and linear vascular pattern with surrounding collarette scale as well as a white-to-pink halo.

Histologically, eccrine poromas are relatively easy to diagnose, with a clear margin between adjacent normal epidermal keratinocytes and smaller cuboidal cells, which have a Periodic acid-Schiff positive compact eosinophilic cytoplasm and darker nuclei, protruding down into the underlying dermis.[6]

Eccrine poroma needs to be differentiated from conditions having similar clinical and dermoscopic features such as the reddish-white globule-like structures, which are also seen in hemangioma or pyogenic granuloma and the milky-red areas also found in melanoma.[7]

If the lesion recurs after excision or presents with ulceration, bleeding, pain, or accelerated growth, eccrine porocarcinoma can be suspected. In contrast to porocarcinoma, recurrence of eccrine poroma is rare. Porocarcinoma commonly involves hands and feet, but rarely can involve scalp, face and eyelids.[5] It has a pink, moist, shiny surface which appears as a nodule, dome-shaped, infiltrated, erosive plaque which tends to ulcerate as in our case. Histology shows intra-epidermal and dermal nests and cords of epithelial cells with pale cytoplasm. The tumor masses form clearly demarcated and frequently rounded nests of polygonal cells with pleomorphic and irregularly shaped nuclei, prominent nucleoli and numerous mitotic figures.[8] These findings were not observed in our case.

Dermoscopy of eccrine porocarcinoma shows combination of atypical vascular pattern and milky-red globules.[9]

One of the other differentials of eccrine poroma is nodular type of basal cell carcinoma(BCC) which comprises about 60–80% of the cases of BCC, commonly seen on the head and neck in middle aged or elderly individuals. Clinically it presents as elevated, exophytic pearl-shaped nodules with telangiectasia on the surface and periphery. Histology reveals nest-like infiltration of basaloid cells with atypical peripheral pallisading of the cells and chaotic arrangement of the cells in the central region. Vascular pattern in poroma is considerably in less focus than the arborizing vessels of BCC, suggesting that vessels in the poroma are located much deeper in the dermis.[10]

Superficial lesions of eccrine poroma are treated with simple excision or with shave or electrosurgical destruction, while deeper lesions with simple excision.

Eccrine poroma has close resemblance to several other dermatologic conditions, clinically and histopathologically. A correct diagnosis of the clinically elusive eccrine poroma can be achieved through biopsy, immunohistochemical staining, and dermatoscopic evaluation.

References