Desmoid tumour of the external ear and mastoid following middle-ear surgery.

BACKGROUND: Desmoid tumours (aggressive fibromatosis) are rare, locally invasive, benign tumours. The following case represented a diagnostic challenge, because of the uncommon nature of the lesion. CASE REPORT: A 26-year-old woman, who had previously undergone middle-ear surgery for cholesteatoma, presented with a painful swelling involving the post-auricular area and the conchal bowl. Initially, it was believed to be an infective process related to the surgery or an unusual cholesteatoma recurrence. Following investigations, which involved imaging and histology, the swelling was diagnosed as a desmoid tumour, and the patient received chemotherapy. CONCLUSION: Two incidences of paediatric desmoid tumours affecting the ear have been described in the literature, but there is no previous report of a desmoid tumour related to ear surgery. Desmoid tumours have, however, been reported following trauma, including surgery.

A 39-year-old woman presented to the Emergency Department with dysuria and persistent abdominal pain for several weeks. The pain increased with palpation. Physical examination was otherwise normal. Computerized tomography (CT) scan revealed a round structure of unknown origin against the caecum and terminal ilium suspect for a GIST tumor and a fluid-filled right uterine tube suggestive of pyosalpinx. The following day a laparoscopic surgery with removal of the pyosalpinx and complete right hemi-colon including the suspected lesion was performed and biopsies of the surrounding peritoneum, meso and ileum were taken. Immunohistochemical tests (CD117/DOG1) and molecular analysis (KIT/PDGFRA) ruled out GIST. SMA and desmin were also negative. β-catenin along with next generation sequencing which revealed a likely pathogenic mutation in exon 3 of the CTNNB1 gene, suggested a diagnosis of desmoid-type fibromatosis (DF). Biopsies of the lymph nodes were negative.

To demonstrate the feasibility of percutaneous microwave ablation in desmoid fibromatosis with respect to tumor volume control and improvement in the quality of life. Twelve microwave ablations were performed in 9 patients with a histological diagnosis of desmoid fibromatosis between January 2010 and January 2019. The study population included 6 female and 3 male, with an age range of 21-76 years (mean = 46.6 years; standard deviation [SD] = 19.3 years). The mean major axis of the tumors was 10.9 cm (SD = 5.2 cm) and mean lesion volume was 212.7 cm³ (SD = 213 cm³). Their anatomical distribution was as follows: 3 lesions in the thigh, 2 in the gluteus, 2 in the leg and 2 in the periscapular region. We evaluated the reduction in tumor volume and improvement in the quality of life based on the Eastern Cooperative Oncology Group (ECOG) scale. An average tumor volume reduction of 70.4% (SD = 24.9) was achieved, while the quality of life (ECOG scale) improved in 88.9% of patients. Percutaneous microwave ablation may potentially be a safe, effective, and promising technique for controlling tumor volume and improving the quality of life in patients with desmoid fibromatosis.

Introduction and importance: Desmoid fibromatosis is a benign monoclonal fibroblastic tumor that was first reported in 1832 and arises from musculoaponeurotic structures. It is an uncommon tumor that can mimic breast carcinoma in both hits clinical and radiological presentation. This entity mainly affects patients in their fourth and fifth decades of life. Case presentation: Our four patients were of young women in their 2nd and 3rd decade that consulted for masses of the breast. These lesions were suspicious for malignancy in both their clinical and radiological features despite not having any family history of breast carcinoma. Clinical discussion: Only histology provides the diagnosis, it is locally invasive, non-metastatic but with a high potential of recurrence and the sole treatment is complete and wide local excision with clear margins. Conclusion: Although it is a rare clinical scenario, the presence of an unusual breast or chest wall tumor such as a desmoid tumor should be considered when obvious breast changes and history do not correlate with routine diagnostic measures.

Sinonasal myxoma (SNM) is a rare benign mesenchymal tumor that arises in the sinonasal cavity or maxilla and almost exclusively affects young children. Currently, it is considered a specific entity, but its molecular characteristics have not been reported. Lesions diagnosed as SNM and odontogenic myxoma/fibromyxoma (OM/OFM) were identified from the participating institutions, and the clinicopathologic features were recorded. Immunohistochemistry for β-catenin was performed on all cases with available tissue. Next-generation sequencing (NGS) was performed on all SNM cases. Five patients with SNM were identified, including 3 boys and 2 girls with an age range of 20-36 months (mean: 26 months). The tumors were well-defined, centered in the maxillary sinus, surrounded by a rim of woven bone, and composed of a moderately cellular proliferation of spindle cells oriented in intersecting fascicles in a variably myxocollagenous stroma that contained extravasated erythrocytes. Histologically, the tumors resembled myxoid desmoid fibromatosis. Three tested cases showed nuclear expression of β-catenin. In 3 tumors, NGS revealed intragenic deletions of APC exons 5-6, 9 and 15, or 16, respectively, with concurrent loss of the other wild-type copy of APC, predicted to result in biallelic inactivation. The deletions were identical to those that occur in desmoid fibromatosis, and copy-number analysis raised the possibility that they were germline. In addition, one case showed possible deletion of APC exons 12-14, and another case exhibited a CTNNB1 p.S33C mutation. Ten patients with OM/OFM were identified, including 4 women and 6 men (mean age: 42 years). Seven tumors involved the mandible, and 3 the maxilla. Histologically, the tumors differed from SNM, and all cases lacked nuclear expression of β-catenin. These findings suggest that SNM represents a myxoid variant of desmoid fibromatosis that often arises in the maxilla. Because the APC alterations might be germline, genetic testing of the affected patients should be considered.

We report a case of a relatively large desmoid fibromatosis that responded completely to tamoxifen as a single drug therapy. A 47-year-old Japanese man underwent laparoscopy-assisted endoscopic submucosal dissection for a duodenal polyp. He developed postoperative generalized peritonitis and underwent an emergency laparotomy. Sixteen months after the surgery, a subcutaneous mass was found on the abdominal wall. Biopsy of the mass revealed estrogen receptor alpha-negative desmoid fibromatosis. The patient underwent total tumor resection. Two years after the initial surgery, he was found to have multiple intra-abdominal masses, with the largest mass measuring 8 cm in diameter. Biopsy revealed fibromatosis, as in the case of the subcutaneous mass. Complete resection was impossible due to the proximity of the duodenum and superior mesenteric artery. Tamoxifen was administered for three years, resulting in complete regression of the masses. No recurrence was observed for the following three years. This case indicates that relatively large desmoid fibromatosis can be successfully treated with a selective estrogen receptor modulator alone and that its effect is not dependent on the estrogen receptor alpha status of the tumor.