Eccrine porocarcinoma (EPC) is a rare skin cancer of the intraepidermal ductal portion of
the sweat gland, accounting for 0.005 - 0.01% of all malignant epithelial tumors. Owing to
the rarity, treatment of metastatic EPC is not standardized. Herein, we present a case of
drastic response to cetuximab and 5-FU/LV of a metastatic EPC with EGFR amplification.
A 70-year-old woman was referred to us for the treatment of EPC. She had been
undergone to excision of a skin lesion in her left breast and axillary lymph nodes before
reference to our hospital. However, 6 months later, a computed tomography (CT) scan
revealed lung metastases and a liver metastasis. Immuno-histological staining of the
primary lesion showed the following: Ki-67 95%, EMA(+), CK5/6(+), p40(+), p63(+), AR(+),
MUC1(+), ER(±), PgR(-), HER2(2+), HER2-FISH(-), GCDFP15(-), GATA3(±), PAX5(-),
S100(-). As an initial chemotherapy, carboplatin and docetaxel were administered every 3
weeks. After 5 cycles, CT scan showed disease progression in lung metastases and
appearance of hepatic lymph nodes metastases.
We performed a comprehensive genomic profiling (CGP) by FoundationOne ®CDx and
identified EGFR amplification (copy number 53). The result of genomic profiling is shown in
Table 1. Based on this result, cetuximab (400 mg/m 2 once, then 250 mg/m 2 per week) in
association with 5-FU/LV (200 mg/m 2 leucovorin, 400 mg/m 2 bolus fluorouracil, and 2400
mg/m 2 infusional fluorouracil per 2 weeks) were administered. All lesions were shrunk
drastically and kept under control without progression for more than a year. Grade 3
hypomagnesemia was observed but manageable.
Given the few cases and the absence of clinical trials in rare cancers, it is important to
collect clinical experiences on rare cancers, especially the cases with the efficacy by the
treatment based on CGP. Our experience suggests a potential role of EGFR inhibition in
advanced EPC, which can help physicians treat this rare and aggressive skin cancer.
|Tumor Mutational Burden||1 Muts/Mb|
EGFR amplification (copy number 53)
MYC amplification (copy number 6)
Table 1. Comprehensive genomic profiling by FoundationOne ®CDx