Introduction
Eccrine poromas are benign adnexal neoplasms that typically occur as solitary lesions in regions with a high density of sweat glands such as the palms and soles. Though the term ‘eccrine’ poromas has been traditionally used, these lesions may be of either apocrine or eccrine lineage. Clinically, the lesions appear as pink, red, flesh-colored, or blue pigmented papules or nodules with smooth or verrucous surfaces. Treatment with surgical excision is often considered optional given the benign course of poromas. Herein we report a patient who presented with a slow growing nodular lesion over the left palm which was later histopathologically confirmed to be case of Eccrine Poroma.
Case description
A 65-year-old male patient presented with a single, dark-colored, raised lesion on the left palm since 10 years. It gradually increased in size over the previous 2 years and was associated with pruritus and bleeding on touch. There was no other significant history and other family members were not affected. General examination was unremarkable. Cutaneous examination revealed well-circumscribed, nontender, sessile hyperpigmented nodule measuring 2 cm in diameter on the hypothenar eminence of left palm [Figure 1]. There was no similar lesion elsewhere on the body. The hair, nails, and mucosae were normal. The differential diagnoses that were considered were pyogenic granuloma, poroma, verruca vulgaris, basal cell carcinoma, and dermatofibroma [Table 1]. The nodule was completely excised and histopathological finding showed an epithelial neoplasm arising from the lower portion of epidermis and extending downward into the dermis. There were two types of cells seen, one type was cuboidal cells that were smaller and darker stained, while the other type was cuticular cells that were pink in color and larger. Both types of cells were monomorphous cells with rounded nuclei. Moderate amount of melanin pigment was present within the epithelial component. The stroma showed abundant mucin, edema, and dilated capillaries [Figure 2] [Figure 3] [Figure 4]. Based on the clinical and histological findings, diagnosis of eccrine poroma was made.
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Figure 1: Hyperpigmented well-circumscribed nodule on the hypothenar eminence of left palm.
Figure 2: H and E (4×) epidermis with hyperkeratosis and broad anastomosing bands of epithelial cells extending deep into dermis.
Figure 3: H and E (10×) anastomosing bands of cuboidal cells.
Figure 4: H and E (40×) uniform small cuboidal cells with round nuclei and moderate amount of cytoplasm.
Table 1: Differential diagnoses of eccrine poromas
Discussion
Eccrine poroma was first described by Goldman et al. in 1956.[1] The term “poroma” refers to a group of benign neoplasm of acrosyringium with “poroid” or terminal ductal differentiation. Clinically, poromas usually present as solitary, moist, flesh colored, exophytic, painful, sessile or pedunculated papules, plaques, or nodules usually over the palms and soles but may also appear on any cutaneous surface, where they tend to mimic benign and malignant melanocytic and nonmelanocytic lesions. About two-third of cases are seen on soles or sides of soles followed by hands and fingers, and rarely over the face. Most of the lesions appear in middle-aged or elderly individuals.[2] Histopathologically, eccrine poroma arises within the lower portion of the epidermis and it extends downward into the dermis as tumor masses that often consists of broad anastomosing bands of epithelial cells.[3] The cells are smaller than epidermal keratinocytes, have a uniform cuboidal appearance, and a round deeply basophilic nucleus. Most eccrine poromas show ductal lumina and occasional cystic spaces within the tumor bands which are lined by an eosinophilic, periodic acid-Schiff (PAS)-positive, diastase-resistant cuticle. Dermoscopy of eccrine poroma is characterized by a vascular pattern, which may be polymorphous. Glomerular, hairpin vessels, and linear irregular vessels, surrounded by a white to pink halo, may be observed. Reddish-white globule-like structures are occasionally seen, mimicking the red lacunae typical of vascular lesions, such as hemangioma or pyogenic granuloma. Milky-red areas, commonly found in melanoma, may also be present. Pigmented globule-like structures, comedo-like openings, as well as blue-gray ovoid nests, arborizing vessels, and maple leaf-like structures similar to those of pigmented basal cell carcinomas are also described in pigmented variants of eccrine poroma.[4]
Poromas, being benign adnexal neoplasms; treatment is optional. Electrosurgical destruction, carbon dioxide laser-assisted removal, or surgical excision may be performed. Topical treatments such as 1% atropine solution have been reported to be beneficial in treatment of superficial lesions.[2]
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
Authors thank Dr Balkrishna Pralhadrao Nikam for their help in this study.
REFERENCES
1. Goldman P, Pinkus H, Rogin JR.
Eccrine poroma; tumors exhibiting features of the epidermal sweat duct unit AMA Arch Derm. 1956;74:511–21
2. Mahajan RS, Parikh AA, Chhajlani NP, Bilimoria FE.
Eccrine poroma on the face: an atypical presentation Indian J Dermatol. 2014;59:88–90
3. Wankhade V, Singh R, Sadhwani V, Kodate P.
Eccrine poroma Indian Dermatol Online J. 2015;6:304–5
4. dos Santos BS. Clinical and dermoscopic features of
eccrine poroma Indian J Dermatol Venereol Leprol. 2015;81:308–9
