Purpose Perianal abscesses are common presentations, resulting from infection of the anal glands. However, rare cases of underlying malignancies masquerading as benign abscesses can pose significant diagnostic challenges and lead to delayed management. Case A 49-year-old woman presented with an enlarging right gluteal mass over a nine-month period, initially suspected to be a perianal abscess. However, as the mass failed to resolve clinically, an MRI revealed an extensive lesion invading the ischiorectal fossa and histopathology confirmed it as angiosarcoma. Preoperative staging with PET scans identified hypermetabolic foci in the right posterior ilium, leading to the initiation of a weekly paclitaxel chemotherapy regimen. She later underwent palliative surgical excision, which left a 10x10 cm para-gluteal defect. Reconstruction was achieved using an islanded superior gluteal artery perforator flap to restore the region's contour and volume. Results This case underscores the critical role of histopathological analysis in cases of refractory or atypical perianal abscesses. Clinicians should maintain a high index of suspicion for malignancy in recurrent or non-healing lesions. Early recognition and multidisciplinary management, including surgery, radiotherapy, and chemotherapy, are essential to improve outcomes in this rare and aggressive disease. Conclusion This case highlights the rarity of cutaneous angiosarcomas in the gluteal region and demonstrates a practical reconstructive approach for maintaining both bulk and contour in this anatomically challenging area.