Management of Adnexal Carcinoma on Skin Biopsy
Wide local excision with adequate margins is the treatment of choice for adnexal carcinoma, and all patients should undergo multidisciplinary review to determine the need for imaging, lymph node evaluation, and adjuvant therapy. 1, 2, 3
Immediate Next Steps After Diagnosis
Multidisciplinary Tumor Board Review
- All patients with adnexal carcinoma require presentation at a multidisciplinary tumor board to review histology, plan staging workup, and determine optimal treatment strategy. 2, 3
- This is particularly critical because adnexal carcinomas are rare, locally aggressive, and have variable behavior depending on subtype (eccrine, apocrine, follicular, or sebaceous). 4, 3
Pathology Review Requirements
- Ensure the pathology report includes: tumor depth, degree of differentiation, presence of perineural or lymphovascular invasion, and invasion of deeper structures. 5, 6
- If the initial biopsy was superficial or shows tumor transection at the base, repeat biopsy to the deep reticular dermis is recommended to accurately assess aggressive features. 7, 8
Risk Stratification and Staging Workup
Clinical Examination
- Perform careful palpation of regional lymph node basins, as adnexal carcinomas can metastasize to regional nodes. 7, 6
- Document tumor size, anatomic location, and any symptoms suggesting deeper invasion (altered sensation, fixation to underlying structures). 7
Imaging for High-Risk Features
- For tumors ≥5 cm in diameter or overlying anatomically complex sites, obtain MRI (preferred) or CT to assess tumor extent and involvement of underlying structures including tendons, nerves, vessels, and bone. 5, 6
- MRI is superior to CT for evaluating soft tissue extension and neurovascular involvement. 5, 6
Lymph Node Evaluation
- If lymph nodes are clinically palpable, perform ultrasound-guided fine needle aspiration (FNA) to assess for metastatic disease. 6
- If FNA is inconclusive with persistent clinical suspicion, proceed to surgical biopsy. 6
- For high-risk tumors (≥5 cm, deep invasion, perineural involvement), obtain FDG-PET/CT to evaluate for systemic and lymph node metastases. 5, 6
Definitive Treatment
Surgical Management
- Wide local excision is the treatment of choice for adnexal carcinomas, with the goal of achieving histologically negative margins. 5, 1, 2
- Mohs micrographic surgery can be considered for large tumors or those in cosmetically/functionally sensitive areas to maximize tissue preservation while ensuring complete excision. 1
- In cases where wide excision is not feasible due to extensive local invasion, amputation of the digit or limb may be necessary, particularly for upper extremity lesions. 5
- If regional lymph node metastases are confirmed by FNA or surgical biopsy, regional lymph node dissection should be performed. 5
Adjuvant Radiotherapy
- Adjuvant radiotherapy should be considered for locally advanced disease, positive margins that cannot be re-excised, perineural invasion, or regional lymph node involvement. 2, 3
- The role of radiotherapy is not fully defined but appears beneficial in reducing local recurrence in high-risk cases. 2
- Radiotherapy may also be used palliatively for inoperable tumors or metastatic disease. 5, 2
Systemic Therapy
- Chemotherapy experience is extremely limited for adnexal carcinomas, and these tumors are generally chemoresistant. 1, 9
- Combination chemotherapy appears superior to single-agent treatment in the rare cases where systemic therapy is attempted. 1
- Targeted therapy based on molecular profiling may offer future therapeutic options, but current evidence is insufficient to make specific recommendations. 9, 3
Surveillance and Follow-Up
Monitoring Schedule
- Schedule surveillance examinations every 3 months for the first 2 years to monitor for local recurrence, regional lymph node involvement, and new primary tumors. 5, 6
- After 2 years, adjust frequency based on individual risk factors, but maintain at least annual complete skin examinations. 7
Critical Pitfalls to Avoid
- Do not perform elective lymph node dissection without evidence of lymph node involvement, as this causes significant morbidity including regional lymphedema without proven survival benefit. 7
- Local recurrence is frequent with incomplete surgical removal, so ensure adequate initial excision margins and consider Mohs surgery for complex cases. 1, 2
- Metastatic disease, though rare, carries a poor prognosis, emphasizing the importance of adequate initial staging and treatment. 1, 9
Prognosis and Patient Counseling
- Patient outcomes depend on tumor size, mitotic count, presence of perineural or lymphovascular invasion, and completeness of surgical excision. 2
- Eccrine porocarcinoma is the most frequent adnexal malignancy and demonstrates more aggressive behavior compared to other non-melanoma skin cancers. 9
- Adnexal carcinomas are locally aggressive, infiltrate surrounding tissue, and can metastasize to regional lymph nodes, requiring aggressive initial management. 2, 3