Rare case of large eccrine poroma of the eyelid

Abstract

Eccrine poroma is a rare tumor arising from sweat glands with common location being soles and palms. We are reporting a case of 70-year male patient with large lower lid mass lesion. Owing to its location and history of growth, malignancy was suspected. Biopsy proved it to be eccrine poroma which is a benign lesion. Complete excision with lid reconstruction was done. Eccrine poroma, though rare, should be kept in the differential diagnosis of eyelid tumors. Owing to the risk of malignant transformation and difficulty in clinical differentiation between poroma and porocarcinoma, wide excision should be done.

Introduction

Eyelid tumors comprise a diverse group of neoplasms ranging from benign lesions like squamous papillomas to malignant tumors like basal cell carcinomas. It is important to differentiate benign from malignant eyelid masses as management protocols differ in both cases. We present a case of 70-year-old male with large mass lesion in the lower lid. Histopathology confirmed the diagnosis of eccrine poroma, which is a rare tumor for this site. Diagnosis of this rare tumor highlights the importance of keeping rare tumors of sweat glands in the differentials of eyelid tumors. This case also demonstrates the importance of performing incisional biopsy of eyelid tumors to confirm the diagnosis before proceeding to final surgical intervention.

Case report

A 70-year male patient presented with slowly growing mass lesion arising from lower lid of the Right eye (OD) for the past 15 years. It was painless with no discharge. There was no history of rapid increase in size, recent change in architecture or surface of tumor. Left eye (OS) did not have any eyelid lesions. Patient had not undergone any treatment for the lesion.

OD eyelid examination revealed large mass lesion of lower lid with the maximum dimension being 40 mm(Fig. 1-A). It was reddish-pink in color, broad based with irregular surface, small ulceration at two points, no discharge or bleeding points, and no telengiectatic vessels on the surface. It was firm in consistency, adhered to skin but free from deeper tissues, non-tender, and non-pulsatile. The surrounding eyelid skin appeared normal. Upper eyelid was uninvolved.

Fig. 1.

A: Large lower lid tumor (black arrow). B: 9 months postoperative image with no recurrence in tumor.

Best corrected visual acuity was 6/18, N12 OD and 6/12, N8 OS. Slit lamp examination demonstrated a healthy palpebral and bulbar conjunctiva. Patient had immature senile cataract OU. Rest anterior and posterior segment evaluation was normal.

Systemic examination revealed no lymphadenopathy or any similar lesions in any other part of the body.

Based on the clinical picture, squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) were considered in the differential diagnosis.

Histopathology

Incisional biopsy of the mass was done, and histopathological examination revealed eccrine poroma. On hematoxylin and eosinophil staining, the tissue consisted of uniform cuboidal poroid cells with clear eosinophilic cytoplasm and centrally placed basophilic nuclei. Presence of cystic spaces and tubular structures were also seen. These cells formed broad anastomosing bands between epidermis and dermis (Fig. 2).

Fig. 2.

Cuboidal poroid cells forming broad anastomosing band between epidermis and dermis. Uniform cuboidal poroid cells with clear eosinophilic cytoplasm and centrally placed nuclei. (H&E x40). H&E, hematoxylin and eosinophil.

Treatment

Based on the histopathology report, wide local excision of the lesion was done with lid reconstruction. Histopathological evaluation of the excised mass confirmed eccrine poroma and did not reveal any features of malignant transformation. Margins of the excised tumor were normal and free of any poroid cells.

Till the last follow-up, 9 months postoperatively, there was no tumor recurrence (Fig. 1B).

Discussion

Common differentials of eyelid mass lesions in an older age group are SCC, BCC, melanomas, and sebaceous cell carcinomas. It is important to differentiate these malignant lesions from benign ones. In our case, because of age of the patient, location of mass, and size of mass, malignant tumors were considered first in the differentials. Our case also highlights the importance of performing incisional biopsy in all cases of eyelid tumors before undertaking excisional surgery as the approach to benign lesions is different from malignant tumors.

Various benign lesions may appear as lower lid mass lesions. They may present as sharply demarcated, pigmented macules which may develop irregular surface and stuck on skin appearance (Seborrheic keratosis) or as reddish polypoidal masses which are prone to bleeding (Pyogenic Granuloma) or hyperkeratotic skin colored epidermal outgrowths (Verruca) or as small pedunculated skin colored lesions (Fibroma).

SCC appear as shallow ulcerated lesions with heaped up margins and crusting, whereas BCC appears as a pearly mass with telangiectatic vessels and ulceration or bleeding points. Our case had two small points of ulceration, but they were not associated with any of the above mentioned features suggestive of malignant nature.

Management of invasive malignant tumors like porocarcinoma, SCC, BCC, or sebaceous cell carcinomas require wide local excision, whereas benign tumors can be removed with little margin which prevents unnecessary tissue excision and helps in reconstruction.

Sweat gland tumors are commonly found on soles or palms.^{1, 2, 3} Chen et al. found limb and trunk as more common site in analysis of 25 cases of poroid neoplasms in Taiwan.⁴ Eccrine Poromas arise from intraepidermal portion of eccrine sweat gland ducts. While lesions like hidrocystoma and syringioma are common on eyelid skin, there are very few case reports of eccrine poroma arising from eyelids.^{5, 6, 7} There are also very few case reports of eccrine porocarcinoma of eyelids.^{8, 9, 10, 11}

Sweat gland lesions should be kept in the differentials of any eyelid mass lesions. Poroid neoplasms can be benign like eccrine poroma, hidroacanthoma simplex, or poroid hidroadenoma with eccrine poroma being the most common among these.⁴ Eccrine porocarcinoma is an invasive malignant tumor of the sweat gland which can evolve de novo or from preexisting eccrine poroma.^{12, 13, 14} Because the confirmation of diagnosis and differentiation between these benign and malignant neoplasms can only be done on histopathology, tissue biopsy is mandatory before excisional surgery.

As in our case, it is difficult to clinically distinguish benign poroma from malignant porocarcinoma. Recent changes in the tumor-like bleeding, ulceration, and sudden enlargement were shown to be associated with malignant transformation by Sgouros et al.¹⁵ Though there were two solitary small points of ulceration in our case, there was absence of rolled or heaped up edges, telengiectatic vessels, or bleeding points, indicating a benign pathology.

On histology, poroid cells are identified by their monomorphism with eosinophillic cytoplasm and basophilic oval nuclei. Origin of poroma can be intraepidermal, intradermal, or mixed. Usually, the nests of poroid cells are well delimited from surrounding epidermis.

In our case, atypical cells or asymmetric architecture, suggestive of malignant nature of lesion, was not seen. Cytological pleomorphism, which is a feature of malignancy, was also absent.

On immunohistochemistry, carcinoembryonic antigen, and cytokeratins, CAM-5.2 positivity is seen only in porocarcinomas, whereas epithelial membrane antigen positivity is seen with both poroma and porocarcinomas.

Histologically or dermoscopically, some parts of porocarcinoma may demonstrate features resembling poroma.^12,14 Owing to these factors, all eyelid eccrine poromas should be surgically excised with wide local excision, as was done in our case. Cases where eccrine porocarcinoma has been confirmed on histopathology examination, surgery should be done using Moh's micrographic surgery technique rather than wide local excisions.^16,17

As there is risk of malignant transformation into porocarcinoma, detailed histopathological examination of such large excised mass should be done including margins, and patient should be followed up regularly.¹³ Another unique feature of our case was that inspite of a long history (15 years) and growth of mass to such large proportions, there was no evidence of malignant transformation.

Conclusion

Eccrine poroma is a rare tumor of sweat glands with eyelid being an uncommon site. Owing to risk of malignant transformation and difficulty in clinically differentiating it from malignant porocarcinoma, wide local excision should be performed. It should be considered in the differential diagnosis of eyelid tumors.

Disclosure of competing interest

The authors have none to declare.