BACKGROUND: Schwannoma is an extremely rare benign tumour of the peripheral nervous system; its association with breast cancer is sporadic, and its association with the brachial plexus is extremely rare. CASE DESCRIPTION: The authors report a case of a patient with breast cancer associated with nodulation in the left supraclavicular fossa, and due to the clinical and radiological features, it was considered metastatic lymph node disease. The patient underwent neoadjuvant chemotherapy, with partial response of the breast. Surgical treatment included resection of the supraclavicular nodule, which was found to be a supraclavicular fossa schwannoma. The correct diagnosis, influences the radiotherapeutic planning. The unusual presentation led to diagnostic confusion in the present case, a fact that changed the breast treatment. CONCLUSION:The best of our knowledge it is the third description of brachial plexus schwannoma associated with breast cancer and the first with a synchronous association. The knowledge of this pathology and its potential to alter treatment justify the reporting of the present case.

Background Stewart Treves–Syndrome (STS) was first characterized as angiosarcoma in the homolateral limb of a patient with breast cancer and lymphedema. Now, other conditions represent STS. It's a rare condition. The diagnosis is easier in the presence of single or multiple purple nodules. Even though other dermatological aspects have been reported, no study has grouped its characteristics. Aim Evaluate the dermatological characteristics of classical STS (c‐STS). Methods and Results We report a patient with chronic lymphedema with a history of recurrent erysipelas that rapidly developed multiple papules in the superior limb. It was initially diagnosed as bullous erysipelas, but unsatisfactory evolution led to biopsy, which demonstrated an unsuspected epithelioid angiosarcoma. We have also performed a review of dermatologic aspects of c‐STS using PubMed and Lilacs databases. PICTOS methodology and PRISMA flow chart were considered. The main dermatological aspects associated with c‐CTS were summarized. Using a systematic evaluation from 109 articles, 29 were selected and 44 patients were described to whom we added one case. The mean time with lymphedema was 10 years. Of the patients analyzed, 97.2% were female; 95.6% were submitted to radical mastectomy; 81.2% presented with multiple lesions, 67.4% of the lesions were reported as nodules or tumors, 53.4% were purple, 33.4% were associated with an ecchymotic halo, and 33.4% were ulcerated lesions. Conclusion When evaluating patients with chronic lymphedema with new dermatological abnormalities, clinical suspicion, or unfavorable evolution, the knowledge of clinical signs is important for diagnosis, and a biopsy must be considered. Papules associated with erythematous‐wine color and bluish hematoma aspect must raise clinical suspicion.