Indian Dermatology Online Journal

: 2019  |  Volume : 10  |  Issue : 2  |  Page : 190--192

SkinIndia Quiz 50: Solitary growth on the arm

Krishna Talukdar1, Debdeep Mitra2, Neerja Saraswat2, Ajay Chopra2,  
1 Department of Dermatology, Jorhat Medical College and Hospital, Joerhat, Assam, India
2 Department of Dermatology, Base Hospital, Delhi Cantt, New Delhi, India

Correspondence Address:
Debdeep Mitra
Department of Dermatology, Base Hospital Delhi Cantt, New Delhi - 110 010

How to cite this article:
Talukdar K, Mitra D, Saraswat N, Chopra A. SkinIndia Quiz 50: Solitary growth on the arm.Indian Dermatol Online J 2019;10:190-192

How to cite this URL:
Talukdar K, Mitra D, Saraswat N, Chopra A. SkinIndia Quiz 50: Solitary growth on the arm. Indian Dermatol Online J [serial online] 2019 [cited 2021 Dec 8 ];10:190-192
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Full Text

A 28-year-old lady presented with an erythematous sessile and slightly pedunculated firm nodule measuring approximately 5 Χ 3 cm over the left upper arm with ulceration at points of pressure for one year [Figure 1]. The growth was initially very minute, pinhead-sized, which gradually increased with time. It was associated with dull aching intermittent pain, mild intermittent itching, and few episodes of bleeding. There was no history of trauma on the affected area or any discharge from the growth. The growth was excised 7 months ago but it reappeared with the initial symptoms. There was no significant weight loss. The nodule was tender to touch, mobile in vertical as well as in horizontal directions, not fixed with skin or any underlying structures, and there was no local rise of temperature. The entire lump was excised and sent for histopathological examination.{Figure 1}

Histopathology revealed a well-circumscribed tumor composed of proliferative cuboidal cells that extended from the basal epidermis into the dermal layer as cords and nests of small keratinocytes attached to the epidermis. These were sharply delimited from the adjacent epidermis under low power view [Figure 2]. These cords were strictly intraepidermal along with extension to superficial dermis, and the dermis showed reactive blood vessels and inflammatory infiltrate which was appreciated under higher magnification [Figure 3]. No mitotic figures, foci of necrosis en-masse, or any clear cell change with small nuclei surrounded by a pale cytoplasm was noted. The aggregates of keratinocytes did not show any ductal or tubular formation.{Figure 2}{Figure 3}


What is your diagnosis?

 View Answer


Eccrine poroma.


Eccrine poroma, which was first reported by Pinkus in 1956, represents approximately 10% of all sweat gland tumors.[1] It is a benign tumor originating from the intraepidermal ductal portion of the eccrine sweat duct. It is often grouped within the greater classification of acrospiroma that also includes dermal duct tumors, poroid hidradenomas, and hidroacanthoma simplex. They are mostly exophytic bright red to flesh.colored, solitary, moist, painful, pedunculated, or sessile nodule usually occurring on the soles or palms. A distinct clinical feature is a cup.shaped shallow depression

from which the tumor protrudes.[2] Other sites of occurrence of eccrine poroma described in the literature are eyes, chest, and buttocks. Occasionally, eccrine poromas may be pigmented and resemble basal cell carcinoma both clinically and dermatoscopically.[3] Eccrine poromatosis is a rare clinical variant when there is development of multiple poromas occurring in patients on polychemotherapy or radiotherapy.[4] Poromas have also been found to occur in patients with Bowenfs disease and hypohidrotic ectodermal dysplasia.[5] Multiple poromas and porocarcinomas have been described to be associated with human immunodeficiency virus, sarcoidosis, nevus sebaceous, pernicious anemia, Hodgkinfs disease, extramammary Paget's disease, xeroderma pigmentosum, and chronic lymphocytic leukemia.[6]

Although traditionally poromas have been thought to originate from the intraepidermal portion of the sweat gland duct, known as the acrosyringium, consisting of poroid ductal cells that differentiate in the direction of sweat gland ducts, recent literature has shown cases of apocrine cell differentiation as well.[7] It is extremely difficult to differentiate the poroma of eccrine and apocrine origin because of the fact that the sweat ducts of the two are histologically and immunologically similar. However, if poroma on histopathology displays more tubular foci which is lined by columnar cells and have holocrine secretions it is highly suggestive of an apocrine etiology.

Eccrine porocarcinoma, the malignant variant, is more common in elderly patients with a majority of cases occurring in the lower limb. Porocarcinoma evolving from a poroma is characterized by rapid growth up to 10 cm, bleeding, and ulceration.[1] Histopathologically, eccrine poroma originates within the lower half of the epidermis and extends downward into the dermis as cords or nests that often consist of broad anastomosing bands of epithelial cells. The cells have a round deeply basophilic nucleus and a uniform cuboidal appearance and are smaller than the surrounding epidermal keratinocytes.[8] Depending on the location of the poroid cells in relation to the epidermis, a poroma can be categorized into the acrospiroma variants, as

described above. It may be entirely intraepidermal, such as hidroacanthoma simplex, wholly juxtaepidermal when it involves basal layer of epidermis and extends into the superficial part of dermis it is known as classical eccrine poroma, or entirely intradermal such as dermal duct tumors.[9] Poroid and nodular hidradenomas exclusively reside in the dermal layer and are classified based on

whether they show eccrine or apocrine differentiation. Within the epidermis, poroid cells are sharply differentiated from the adjacent keratinocytes. These cuboidal cells have monomorphous ovoid nuclei with a nonpalisading pattern and inconspicuous nucleoli. The cells have a characteristic compact eosinophilic cytoplasm that stains periodic acid.Schiff.positive.[10] In our case, as the poroid cells were extending from lower half of the epidermis onto the dermis; hence, this patient had classical features of eccrine poroma. Immunohistochemistry reveals that poroid cells are positive for cytokeratin (CK) 1/5/10/14, CK 5/8, and CK 14. Lately, studies have found an association of p53 protein expression as a marker for both eccrine poroma and porccarcinoma. Overexpression of p16, as well as loss of retinoblastoma protein, could potentially be used as a useful diagnostic test on routine laboratory screening as it has been recently concluded that p16 gene protein has a positive expression in cases of porocarcinoma and is universally absent in cases of poroma; however, retinoblastoma protein has an inverse relation.[11] As these are benign neoplasms, the best modality of treatment is complete surgical excision. Other options include electrosurgical destruction and carbon dioxide laser.assisted removal.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

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