Nasopharyngeal malignant melanoma masquerading in the gallbladder: the importance of histological assessment.

Metastatic melanoma of the gallbladder is a rare entity that is often diagnosed late, leading to a poor prognosis. The disease may present insidiously as acute cholecystitis or remain asymptomatic. Optimal management remains unclear but surgical resection is considered the mainstay of treatment for this condition. We report the case of a 47-year-old man who suffered a protracted course of generalised abdominal symptoms eventually culminating in a diagnosis of acute cholecystitis. Following an emergency laparoscopic cholecystectomy, the histology revealed a melanoma with an unknown primary. Subsequently this was traced to the nasopharynx. Because of the presence of concurrent liver metastasis, systemic immunotherapy with palliative intent was commenced following a multidisciplinary team discussion. This case highlights the importance of sending clinical specimens for histological analysis. We argue against selectively choosing which specimens to send for histology because radiological and/or intraoperative macroscopic inspection of resected tissue alone can result in a missed diagnosis.

Aggressive angiomyxoma of the ischioanal fossa in a post-menopausal woman.

Aggressive angiomyxoma is a rare mesenchymal tumour, primarily arising in the soft tissue of the pelvis and perineum in women of reproductive age. There is a paucity of evidence on optimal management because of the rarity of these tumours, but the consensus has been for surgical excision. We present the case of a 65-year-old woman who was admitted with left-sided buttock pain and initially diagnosed with a perianal abscess. She underwent examination under anaesthesia rectum with surgical excision of the lesion, subsequent histopathological and immunochemical analysis was suggestive of aggressive angiomyxoma. To complement our case report, we also present a literature review focusing on aggressive angiomyxoma in the ischioanal fossa (also known as the ischiorectal fossa) with only eight cases of primary aggressive angiomyxoma involving the ischioanal fossa documented to date. The primary aims of this case report and literature review are to familiarise clinicians with the clinical, histopathological and immunochemical features of these tumours, and to increase appreciation that despite the rarity of aggressive angiomyxoma, it might be considered in the differential diagnosis of ischioanal lesions.