Introduction:
Eccrine porocarcinoma (EP) is an extremely rare adnexal malignancy, representing only 0.01% of cutaneous tumours. While often slow-growing initially, it carries a high risk of regional metastases. We present a case of distal thigh EP notable for its aggressive spread and significant regional nodal involvement.
Case Description:
A 75year-old patient presented 30 year history of a soft tissue lesion in the left distal thigh, with a rapid increase in size noted over the last year. Staging investigations identified suspicious left inguinal lymphadenopathy with biopsies suggesting undifferentiated carcinoma. The patient underwent wide local excision of the primary tumour and a formal radical inguinal lymphadenectomy.
Histopathological examination diagnosed metastatic Eccrine Porocarcinoma, but most notably revealed 17 positive lymph nodes within the lymphadenectomy specimen. The primary lesion exhibited lymphovascular invasion signalling a highly aggressive phenotype.
Discussion:
The prognosis of EP shifts dramatically upon nodal involvement, with reported mortality rates increasing from 1% to over 60%. A burden of 17 positive nodes is exceptional in the literature and poses a significant therapeutic challenge.
This case highlights the unpredictable biological behaviour of adnexal carcinomas. It underscores the necessity of early regional staging and suggests that in cases of high nodal burden, a multidisciplinary approach—incorporating radical surgical clearance and adjuvant radiotherapy—is essential for regional control.
Conclusion:
EP can mimic common squamous cell carcinomas but requires a higher index of suspicion for aggressive systemic spread. This case serves to alert plastic surgeons to the potential for massive nodal involvement in sweat gland malignancies, necessitating proactive surgical and oncological management.