Mohs micrographic surgery for eccrine porocarcinoma: an update and review of the literature

Porocarcinoma: Clinical and Histological Features, Immunohistochemistry and Outcomes: A Systematic Review

Porocarcinoma (PC) is a rare adnexal tumor, mainly found in the elderly. The tumor arises from the acrosyringium of eccrine sweat glands. The risk of lymph node and distant metastasis is high. Differential diagnosis with squamous cell carcinoma is difficult, although NUT expression and YAP1 fusion products can be very useful for diagnosis. Currently, wide local excision is the main surgical treatment, although Mohs micrographic surgery is promising. To date, there is no consensus regarding the role of sentinel lymph node biopsy and consequential lymph node dissection. No guidelines exist for radiotherapy, which is mostly performed based on tumor characteristics and excision margins. Only a few studies report systemic treatment for advanced PC, although therapy with pembrolizumab and EGFR inhibitors show promise. In this review, we discuss epidemiology, clinical features, histopathological features, immunohistochemistry and fusion products, surgical management and survival outcomes according to stage, surgical management, radiotherapy and systemic therapy.

Navigating Head and Neck Porocarcinoma: Systematic Review with Special Emphasis on Surgical Safety Margins

Eccrine porocarcinoma, sharing many features with other skin tumours, is diagnostically challenging. A conventional biopsy might be misleading and surgical excision becomes a primary diagnostic tool and a treatment method. However, the data on surgical safety margins are not consistent. We present a systematic review analysing the surgical margins of porocarcinoma in the head and neck area, which was conducted across the PubMed, Cochrane, and Web of Science databases including studies published from inception to November of 2023. In this systematic review, the PRISMA-ScR checklist was used, and a Cohen's Kappa coefficient of 0.92 was applied, indicating very good agreement between reviewers. Out of 529 identified articles, 18 studies yielding 20 cases in total were selected for a thorough analysis. Nine (45%) cases were observed in the facial regions, eight (40%) on the scalp, and three (5%) on the neck. The primary treatment of choice was wide local excision with safety margins ranging from 3 to 22 mm (mean: 10.1). It demonstrated that surgical margins do not differ by age or anatomic regions, with the main point of reference being the tumour size. As observed, the bigger the tumour, the wider the safety margins were. However, the limited disclosure of surgical safety margins in analysed case reports impeded our ability to define the minimum safety margins. Further investigation and a consensus on recommended safety margins are required.

Primary Eccrine Porocarcinoma of the Breast: A Case Report and Review of Literature

Eccrine porocarcinoma (EPC) is a rare cutaneous neoplasm, with less than 500 reported cases worldwide since it was first described in 1963. EPC tends to affect the elderly and most commonly affects the head and neck. The mainstay of EPC treatment is surgery, with lymphadenectomy in the case of nodal involvement or presence of unfavourable characteristics. No evidence exists to guide the use of adjuvant chemotherapy or radiation. EPC is prone to misdiagnosis given its multiple clinical and histopathological mimics, especially in uncommon sites of presentation such as the breast. Herein, we report the case of a 59-year-old woman who presented with a left breast skin lump. The biopsied specimen revealed an infiltrative carcinoma involving the dermis and epidermis with positive IHC staining for P63 and CK5/6 and negative staining for ER, PR, and HER2. The tumour was resected and diagnosed as EPC with atypical features as overlapping characteristics of squamous cell carcinoma (SCC) were detected on histopathological analysis. In our case, a simple mastectomy with broad margins and axillary lymph node dissection with adjuvant radiotherapy to a dose of 60 Gy failed to achieve loco-regional control with nodal recurrence occurring 4 months postsurgery-a testament to the aggressive course of this rare malignancy.

A systematic review of periungual eccrine neoplasms

Eccrine tumors are a rare cutaneous adnexal neoplasm originating from the sweat glands. The periungual region represents an uncommon localization for these neoplasms. We analyzed all published demographic, clinical, and treatment data on periungual eccrine tumors. A systematic review following PRISMA guidelines was performed of articles published prior to March 2021. Articles were included in the review if a full-text English version was available. Of the surveyed literature, 27 full-text case reports were included in the final analysis. Benign eccrine poroma and porocarcinoma were the most common tumor subtypes (nine and eight cases, respectively). Males were only affected by poroma and porocarcinoma, while females were affected by all tumor subtypes. The first toe was the most common lower extremity affected. Misdiagnosis led to delayed treatment in 25% of cases. As such, while periungual eccrine neoplasms are rare diagnoses, the nonspecific presentations of these growths raise concerns about misdiagnosis and delayed treatment. Further research is needed related to sex-differences in the epidemiology of these growths and into the prevalence of the first toe as a location. These tumors should be considered in the differential diagnosis for nail unit afflictions.

[Management of malignant adnexal neoplasms of the skin]

Malignant adnexal neoplasms of the skin are a heterogeneous group of rare malignancies with eccrine, apocrine, sebaceous and follicular differentiation. Essential clinical practice recommendations for the overall management of these cancers are presented. Moreover, specific evidence-based findings according to diagnosis, therapy and follow-up of porocarcinoma, sebaceous carcinoma and microcystic adnexcarcinoma will be explained.

Eccrine Porocarcinoma: Avoiding Diagnostic Delay

Skin cancer is the most common cancer within the United States. Reports estimate that 1 in 5 Americans will develop some form of skin cancer. Eccrine porocarcinoma is a rare type of skin cancer of sweat gland origin. Eccrine porocarcinoma is most commonly found on the lower extremities. Clinically it may appear similar to benign skin lesions and it has significant metastatic potential. The authors present a case report with 22 months' follow-up. It describes a multiyear delay in diagnosis involving 3 specialties, including primary care, dermatology, and wound physical therapy. Information is given on techniques when high-risk cutaneous cancers are suspected or encountered. A multispecialty treatment plan is discussed.Levels of Evidence: Level V.

Intergluteal Cleft Eccrine Porocarcinoma with Metastasis to Inguinal Region and Lung: Case Report and Review of the Literature

Eccrine porocarcinoma (EPC) is an infrequent cutaneous neoplasm, and was described in 1963 by Pinkus and Mehregan. It is a rare type of skin tumor (0.005-0.01% of all skin tumors). Less than 300 cases have been described in the entire world medical literature. To our knowledge, no case of intergluteal cleft EPC has been reported in the literature in English and Spanish to date, so this would be the first reported case of such pathology. Metastatic EPC is less frequent, since only <10% of metastatic type have been reported and the rest as localized disease. The primary treatment of choice is surgical wide local excision of the tumor with histological confirmation of tumor-free margins. Prognosis is difficult to determine because of the rarity of EPC and the variations in natural history. There are no data to support the use of adjuvant chemotherapy or radiotherapy, and there are currently no agreed criteria to define patients at high risk of relapse. We present a 67-year-old man with intergluteal cleft eccrine tumor by biopsy. Metastasis to left inguinal region and lung was reported by contrasted abdominal and chest computed tomography. He started chemotherapy based on etoposide, vincristine, carboplatin. A review of pertinent literature is provided.

Eccrine porocarcinoma of the head and neck: Meta-analysis of 120 cases

BACKGROUND

The aim of the study is to analyze potential prognostic factors and to evaluate therapy strategies regarding clinical outcome in patients with eccrine porocarcinoma (EPC) of the head and neck.

METHODS

One hundred and sixteen EPC cases from ninety studies and four authors' EPC cases were included in the meta-analysis.

RESULTS

At an average follow up of 20.48 months, the 3-year overall survival and regional recurrence rate were 70.3% and 19.0%, respectively. Patients without surgical treatment had a significantly worse 3-year overall survival. Mohs microscopic surgery led to significantly less occurrence of regional recurrences compared to wide excision. An ulcerating lesion, high mitotic activity, and lymphovascular invasion were significant prognostic factors.

CONCLUSION

Surgical resection is the cornerstone in the therapy of EPC and represents the therapeutic modality that offers the best chance of disease-free survival. Due to the high probability of recurrence, close follow-ups are strongly recommended.

Zosteriform Lymphangitic Metastases of Eccrine Porocarcinoma

Eccrine porocarcinoma (EPC) is a rare malignant neoplasm which originates from the intraepidermal portion of eccrine sweat glands or acrosyringium. Here, we report a unique case of cutaneous metastases of EPC presenting with an erosive plaque on the left thumb and multiple nodules on left forearm. The histopathological examination of the wrist lesion revealed islands of basaloid tumor cells with eosinophilic cytoplasm, downward infiltrating growths, ductal differentiation, and intracytoplasmic lumen formations and focally connected to the epidermis. Acrosyringeal differentiation was confirmed by positive immunohistochemical staining using antibodies to carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA) in some of porocarcinoma cells. Lymphatic embolization was shown by immunostaining of podoplanin. To the best of our knowledge, this is the first reported EPC case with a primary lesion on the left thumb and zosteriform growth pattern of lymphangitic metastases on left forearm. Our case highlights the diagnostic challenges and reveals lymphangitic metastasis mode of EPC.

Mohs Micrographic Surgery: Development, Technique, and Applications in Cutaneous Malignancies

Mohs micrographic surgery (MMS) is a specialized technique for treating skin malignancies that offers the highest cure rate by allowing histological evaluation of the entire peripheral and deep margins. MMS also maximally preserves as much uninvolved, normal adjacent tissue as possible, allowing for the best cosmetic and functional outcomes. When used for appropriate indications, this technique is also more cost-effective than other treatment modalities. In this article, the authors will discuss the development of MMS, the steps involved in this procedure, and the indications for this technique. They will also review the use of MMS for basal cell carcinoma, squamous cell carcinoma, melanoma in situ, and some less common skin malignancies.

Adnexal Carcinomas Treated With Mohs Micrographic Surgery: A Comprehensive Review

BACKGROUND

Adnexal carcinomas (ACs) are rare cutaneous malignancies of sweat gland or pilosebaceous origin. Optimal treatment and metastatic potential of AC are poorly defined. Mohs micrographic surgery (MMS) has been increasingly used to treat AC.

OBJECTIVE

To review selected primary cutaneous AC and their treatment outcomes with MMS.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to primary cutaneous ACs.

RESULTS

Sebaceous carcinoma treated with MMS recurred and metastasized in 6.4% and 3.7%, respectively. Primary cutaneous mucinous carcinoma treated with MMS recurred and metastasized in 9.6% and 6.4%, respectively. After MMS, 4.7% of microcystic AC recurred with no reported metastases. After MMS, recurrences and metastases of trichilemmal carcinoma or hidradenocarcinoma have not been reported. Two (4.2%) regional lymph node metastases but no distant metastases or local recurrences have been reported in eccrine porocarcinoma. Squamoid eccrine duct tumor, pilomatrix carcinoma, and spiradenocarcinoma treated with MMS are also reviewed.

CONCLUSION

The rarity of ACs and the lack of comparative data on treatment makes conclusive recommendations on treatment difficult. Recent large case series and reviews suggest MMS is a useful and possibly superior treatment for AC and should be considered if primary cutaneous disease is suspected.

Understanding Mohs Micrographic Surgery: A Review and Practical Guide for the Nondermatologist

The incidence and diagnosis of cutaneous malignancies are steadily rising. In addition, with the aging population and increasing use of organ transplant and immunosuppressive medications, subsets of patients are now more susceptible to skin cancer. Mohs micrographic surgery (MMS) has become the standard of care for the treatment of high-risk nonmelanoma skin cancers and is increasingly used to treat melanoma. Mohs micrographic surgery has the highest cure rates, spares the maximal amount of normal tissue, and is cost-effective for the treatment of cutaneous malignancies. As in other medical fields, appropriate use criteria were developed for MMS and have become an evolving guideline for determining which patients and tumors are appropriate for referral to MMS. Patients with cutaneous malignancies often require multidisciplinary care. With the changing landscape of medicine and the rapidly increasing incidence of skin cancer, primary care providers and specialists who do not commonly manage cutaneous malignancies will need to have an understanding of MMS and its role in patient care. This review better familiarizes the medical community with the practice of MMS, its utilization and capabilities, differences from wide excision and vertical section pathology, and cost-effectiveness, and it guides practitioners in the process of appropriately evaluating and determining when patients with skin cancer might be appropriate candidates for MMS.

Incidence and Clinical Features of Rare Cutaneous Malignancies in Olmsted County, Minnesota, 2000 to 2010

BACKGROUND

The incidence of rare cutaneous malignancies is unknown. Current estimates of rare cutaneous malignancy incidences are based on broad epidemiologic data or single institution experiences, not population-based data.

OBJECTIVE

To determine the incidence of several rare nonmelanoma skin cancers.

MATERIALS AND METHODS

The authors conducted a retrospective chart review of a population-based cohort between the years 2000 and 2010. Residents of Olmsted County, Minnesota, who were diagnosed with a biopsy-proven nonmelanoma skin cancer-excluding basal cell carcinoma and squamous cell carcinoma-were included in this study. The primary outcome was tumor incidence. Additionally, the authors extracted patient demographics, tumor characteristics, treatment modalities, and outcomes.

RESULTS

The age-adjusted and sex-adjusted incidences per 100,000 persons of multiple rare cutaneous malignancies were: atypical fibroxanthoma (1.8), sebaceous carcinoma (0.8), dermatofibrosarcoma protuberans (0.4), microcystic adnexal carcinoma (0.7), eccrine carcinoma (0.4), eccrine porocarcinoma (0.2), and leiomyosarcoma (0.2).

CONCLUSION

The authors report population-based incidences and clinical characteristics for these rare cutaneous malignancies. The immune status and smoking status of patients and the treatment and outcomes of these tumors are reported. Additional studies in a broader population are needed to further define the epidemiology and outcomes of these malignancies.

Treatment of Porocarcinoma With Mohs Micrographic Surgery: The Mayo Clinic Experience

BACKGROUND

Eccrine porocarcinoma (EPC) is a rare malignant adnexal neoplasm with reported metastatic potential and undefined optimal treatment.

OBJECTIVE

This study reviews the clinical characteristics and outcomes of patients with EPC treated with Mohs micrographic surgery (MMS).

MATERIALS AND METHODS

The authors performed a retrospective chart review of patients with EPC treated by MMS at the Mayo Clinic from 1995 to 2013, recording patient demographics, tumor characteristics, MMS stages to clearance, follow-up, recurrence, metastasis, and mortality.

RESULTS

A total of 9 patients underwent MMS for EPC in 19 years. The average age was 64.2 years, with 6 males and 3 females. All patients were Caucasian. The head and lower extremity were the most common locations (44% each), with 1 on the forearm. Of the 9 tumors, 8 were located on the right side of the body. The mean preoperative tumor size and postoperative defect were 2.9 and 7.8 cm, respectively, when 2 outliers were excluded. An average of 1.3 MMS stages was required for clearance. The mean postoperative follow-up was 3.3 years (range: 1-60 months). No tumors treated with MMS recurred, metastasized, or led to disease-related mortality.

CONCLUSION

Mohs micrographic surgery seems to be a useful treatment modality for EPC. This is one of the largest single-center series of EPC treated with MMS.