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Malignant porocarcinoma of the nail fold: A tricky diagnosis

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Malignant porocarcinoma of the nail fold: A tricky diagnosis
Charbel D Moussallem MD1, Nathalie E Abi Hatem MS2, Ziad N El-Khoury MD3
Dermatology Online Journal 14 (8): 10

1. Charbel D. Moussallem, MD, Department of Orthopedic Surgery, Lebanese University, Faculty of Medical Sciences, Beirut Lebanon.
2. Medical Student at the Holy Spirit University of Kaslik, the Medical School, Kaslik Lebanon
3. Chairman of the Orthopedic Surgery Department at Notre Dame Des Secours University Hospital, Byblos Lebanon; Chairman of the Orthopedic Surgery Department at the Holy Spirit University of Kaslik


Malignant eccrine porocarcinoma is a rare tumor of sweat glands with a high local recurrence rate and a tendency to metastatic spread. We present a case of a 77-year-old male patient that presented with a recurrent, periungual porocarcinoma mimicking onychomycosis and ingrown toe nail that was successfully treated by surgical excision. To our knowledge no such case has been described in this location in the English literature.

Case Presentation

A 77-year-old male patient presented with a four-month history of a painful right first toe with erythema and swelling along the lateral side of the nail; this was treated for onychomycosis without success. Later his pain increased especially on trauma even of mild intensity and a development of granulation tissue was noted. A diagnosis of an ingrown toe nail was made by his primary care physician and was treated by surgical excision of the nail and of the granulation tissue. Four months later the patient's symptoms recurred with reappearance of the granulation tissue and polypoid growth and ulceration with swelling of his toe. When he consulted our clinic, due to severe pain he was walking with difficulty on the affected limb. In addition, he had leg pain especially in the calf muscles with swelling. Deep vein thrombosis was diagnosed and confirmed by Doppler ultrasonography. Laboratory tests were all within normal limits including complete bood count, coagulation studies, liver function tests, C-reactive protein, erythrocyte sedimentation rate, urine analysis and chest radiography. He was treated with intravenous heparin and our orthopedic surgery team was consulted for his great toe periungual lesion. Due to extensive involvement of the soft tissue and the severity and recurrence of symptoms, a malignancy was suspected but no palpable inguinal lymph nodes were present, and no distant metastases were detectable by clinical examination. A biopsy was done and the pathology report was consistent with porocarcinoma. Metastatic workup revealed normal findings. Definitive treatment of this condition was made by a surgical amputation of the great toe at the level of the first metacarpophalangeal joint. All tissue was again sent to the pathology laboratory.

Figure 1Figure 2
Figure 1. Photomicrograph of malignant eccrine porocarcinoma (hematoxylin & eosin)
Figure 2. Photomicrograph showing high N:C ratio wit atypia (hematoxylin & eosin)

Histologically the lesion was compatible with malignant eccrine porocarcinoma. It demonstrated a neoplastic proliferation of polygonal cells with irregular nuclei in an anastomosing trabeculae pattern. These cells also showed a very high nuclear/cytoplasm (N:C) ratio. Ductal structures were present and covered by cylindrical epithelium. Both periodic acid Schiff (PAS) and alcian-blue stains were positive in the glandular cells. There was evidence of infiltration of the dermis and hypodermis

Figure 3
Figure 3. Photomicrograph of the tumor invading the dermis (hematoxylin & eosin)

All surgical margins were free of disease. His postoperative period was uneventful. One year later this patient showed no signs of recurrence and is still free of disease.


Malignant eccrine poromas are a rare type of sweat gland carcinoma [1]. They may arise de novo but usually develop in longstanding, benign, eccrine poromas [2]. The tumor was first described in 1963 by Pinkus and Mehregan [3]. Only around 200 cases have been reported in the literature since then. They are most commonly found on the limbs, particularly the legs and feet, and affect adults of either sex with a female predominance.

In a report and review of the literature done by Goedde et al. of 70 cases, 44 patients (62%) had tumors located on the extremities, 13 (19%) on the head and neck region and 12 (17%) on the trunk [4].

These tumors originate from cells of the eccrine duct epithelium, usually in the region of the dermoepidermal junction [5]. They metastasize readily, via lymphatics in the dermis [6]. The local recurrence rate after excision is high, in the range of 11-20 percent [7, 8]. Standard treatment is via wide local excision and, if clinically indicated, block dissection of regional lymph nodes is warranted. Due to the lack of awareness of and rarity of this condition along with the unusual location and high frequency of ingrown toe nail and onychomycosis, our patient was misdiagnosed in the beginning. The delay of treatment was complicated by deep vein thrombosis, most probably related to the fact that the patient was incapable of walking on the affected limb. To our knowledge, in the English literature, this is the first reported case of periungual porocarcinoma of the toe nails. Two other cases of periungual porocarcinomas have already been reported but both were in the nails of the fingers [9, 10].


Porocarcinoma has not been previously published in this location and this tumor must be considered in the differential diagnosis of periungual and subungual tumors. This tumor should be included in the differential diagnosis of clinically apparent ingrown toe nail and more benign conditions like onychomycosis. While recurrence is not uncommon, surgical excision with negative margins remains the best method of treatment.

Acknowledgments to:
1. Maroun D. Moussallem, PhD Candidate Research Assistant, Department of Chemistry and Biochemistry at the Florida State University; for his generous help in editing this manuscript
2. George Aftimos, MD, Chairman of the Pathology Department at the Notre Dame Des Secours University Hospital, for his help in preparing and interpreting the pathology slides


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