DS24: Primary cutaneous mucinous adenocarcinoma: trends in incidence and management from the largest UK reported case series to date

Z. Haider,¹ B. Haq,² P. Gazzani,¹ F. Shah¹ and A. Martin-Clavijo¹

¹University Hospitals Birmingham NHS Trust and ²University of Birmingham, Birmingham, UK

Primary cutaneous eccrine mucinous carcinoma (PCMC) is a rare entity. We present a case series from a single tertiary centre. Data were collected retrospectively from electronic case notes and multidisciplinary team outcomes from 2007 to 2019. Data on patient demographics, lesion characteristics, surgical management, adjuvant treatments, follow-up, recurrences and metastasis were collected. We identified eight patients who had a confirmed diagnosis of PCMC, referred from six different centres. Mean age of presentation was 68·2 years (range 43–87). Five (63%) patients were white British, one (12%) was Asian and one (12%) was black. Both sexes were affected equally and there was no gender predominance (male-to-female ratio 1 : 1). The most common location for a PCMC was on the head and neck region; one lesion was periocular, one lesion was on the scalp, and four (50%) of the lesions were found on the rest of the face. Two lesions (25%) were found on the trunk and limbs. Seventy-five per cent of our patients had clear staging scans. Twenty-five per cent of patients had abnormal findings; solid-organ malignancies were found, but these were not related to PCMC. Half of our cases were treated with Mohs micrographic surgery (MMS) and the other half were treated with wide local excision (WLE) with 1 cm margins. Two patients (25%) with oestrogen receptor-positive immunology were treated with adjuvant endocrine therapy. There were no known recurrences or metastases in our cases. Mean length of follow-up was 52.5 months; the longest follow-up was 12 years for a patient receiving continued adjuvant endocrine therapy. Mortality in our cohort was 25% (n = 2); no deaths were related to PCMC. Our findings are in keeping with the published literature; the average age of occurrence is in the sixth decade of life. PCMC tends to favour the head and neck region and has a good prognosis (Rismiller KP, Crowe DR, Knackstedt TJ. Prognostic factors, treatment, and survival in primary cutaneous mucinous carcinoma: a SEER database analysis. Dermatol Surg 2020; 46: 1141–7). Screening for underlying primary cancers is essential. MMS is the preferred form of surgical treatment as it allows tissue preservation, but use of MMS over WLE does not have any significant differences associated with morbidity or mortality. The role of adjuvant endocrine therapy needs further study. More data are needed to develop optimal management strategies; the present data provide further insight into this rare cancer.