Collision tumor are neoplasms, including two histologically distinct tumors that coexist in the same mass without histological admixture. The incidence of collision tumor is low and is rare clinically.

To investigate ultrasound images and application of ovarian-adnexal reporting and data system (O-RADS) to evaluate the risk and pathological characteristics of ovarian collision tumor.

This study retrospectively analyzed 17 cases of ovarian collision tumor diagnosed pathologically from January 2020 to December 2023. All clinical features, ultrasound images and histopathological features were collected and analyzed. The O-RADS score was used for classification. The O-RADS score was determined by two senior doctors in the gynecological ultrasound group. Lesions with O-RADS score of 1-3 were classified as benign tumors, and lesions with O-RADS score of 4 or 5 were classified as malignant tumors.

There were 17 collision tumors detected in 16 of 6274 patients who underwent gynecological surgery. The average age of 17 women with ovarian collision tumor was 36.7 years (range 20-68 years), in whom, one occurred bilaterally and the rest occurred unilaterally. The average tumor diameter was 10 cm, of which three were 2-5 cm, 11 were 5-10 cm, and three were > 10 cm. Five (29.4%) tumors with O-RADS score 3 were endometriotic cysts with fibroma/serous cystadenoma, and unilocular or multilocular cysts contained a small number of parenchymal components. Eleven (64.7%) tumors had an O-RADS score of 4, including two in category 4A, six in category 4B, and three in category 4C; all of which were multilocular cystic tumors with solid components or multiple papillary components. One (5.9%) tumor had an O-RADS score of 5. This case was a solid mass, and a small amount of pelvic effusion was detected under ultrasound. The pathology was high-grade serous cystic cancer combined with cystic mature teratoma. There were nine (52.9%) tumors with elevated serum carbohydrate antigen (CA)125 and two (11.8%) with elevated serum CA19-9. Histological and pathological results showed that epithelial-cell-derived tumors combined with other tumors were the most common, which was different from previous results.

The ultrasound images of ovarian collision tumor have certain specificity, but diagnosis by preoperative ultrasound is difficult. The combination of epithelial and mesenchymal cell tumors is one of the most common types of ovarian collision tumor. The O-RADS score of ovarian collision tumor is mostly ≥ 4, which can sensitively detect malignant tumors.

• Ovarian collision tumor
• Ovarian-adnexal reporting and data system
• Epithelial tumor
• Serous cystadenoma
• Ultrasound images

• adenoid cystic carcinoma
• case report
• collision tumor
• hypopharynx
• synchronous esophageal carcinoma

• Humans
• Carcinoma, Adenoid Cystic/radiotherapy
• Carcinoma, Adenoid Cystic/surgery
• Carcinoma, Adenoid Cystic/pathology
• Hypopharynx/surgery
• Hypopharynx/pathology
• Larynx/pathology
• Carcinoma, Squamous Cell/radiotherapy
• Carcinoma, Squamous Cell/surgery
• Carcinoma, Squamous Cell/pathology
• Laryngectomy
• Esophageal Neoplasms/surgery
• Esophageal Neoplasms/pathology

• collision cancer
• early esophageal cancer
• endoscopic submucosal dissection
• esophageal adenoid cystic carcinoma
• esophageal squamous cell carcinoma

Tumor collision is the cohesion in a time of 2 tumors in the same space or organ but of different cell lineage.

72-year-old patient with a history of black stools, involuntary weight loss and moderate protein-calorie malnutrition, asthenia, and adynamia; with endoscopic studies with the finding of esophageal candidiasis that leads to taking a rapid test for HIV (human immunodeficiency virus) which is positive; CT (computerized axial tomography) of the abdomen is performed, showing thickening of the cecum and distal ileum, as well as striation of fat in the same area, findings related to a primary neoformative process, for which it is decided to carry out a right hemicolectomy laparoscopically with pathology that reports ulcerated moderately differentiated adenocarcinoma that invades up to the muscle layer, associated with lymphoid proliferation with immunohistochemical findings consistent with lymphoplasmablastic lymphoma, this is probably linked to his diagnosis of HIV, configuring the diagnosis of tumor collision; extension studies with no findings of metastatic neoplastic disease.

Tumor collision is a rare entity, which implies failure in the genomic control and replication sites of different cell lines, which, due to their lineage, have different regulatory processes, all this occurring at the same time in the same tissue.

The casuistry for collision tumors is scarce; even in the reference centers for oncology, the treatment is challenging given the multiple variables to consider, the particularity of each case, and the scarce evidence on the subject.

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Tumor collision is the cohesion of two different tumors in the same space.

• Collision tumor
• Laryngeal cancer
• Laryngectomy
• Rare tumor
• Squamous cell carcinoma

• CD34
• Collision tumor
• Epithelial membrane antigen
• Glut-1
• Neurofibroma
• Palate
• Polymorphous adenocarcinoma

There are many disputes about the definition, diagnosis, therapy, and prognosis of collision tumors.

We describe a rare patient with a collision tumor consisting of neuroendocrine carcinoma (NEC) and squamous cell carcinoma (SCC) in the nasal cavity and paranasal sinus. She received operation, concurrent chemoradiotherapy, and then two cycles of palliative chemotherapy. Follow-up at 12 mo after diagnosis showed that this patient experienced a complete response with no signs of recurrence or metastasis. A literature review of previous 26 cases diagnosed with collision tumor of NEC and SCC in the head and neck was also undertaken.

It is challenging to manage collision tumors because there are two morphologically and etiologically distinct tumors. Well-designed multimodality therapy including surgery and chemoradiotherapy might lead to a long survival in these patients.

• Collision tumor
• Squamous carcinoma
• Neuroendocrine carcinoma
• Chemoradiotherapy
• Head and neck
• Case report

Simultaneous primary cancers are rare in the oropharynx. This report describes the first reported case of a collision tumor of squamous cell and adenoid cystic carcinoma in the soft palate. The patient was immunosuppressed with a history of liver transplantation, smoking and heavy alcohol drinking. He was treated with wide local excision followed by adjuvant radiotherapy with surface acrylic mold brachytherapy. This technique was used instead of external beam radiotherapy in order to minimize toxicity. The patient tolerated the treatment well and with the only acute grade two mucositis at the soft palate and minimal late toxicity. There is no evidence of disease recurrence and the patient continues to maintain excellent quality of speech and swallowing 14 months after treatment completion.

• adenoid cystic carcinoma
• brachytherapy
• collision tumor
• dual primary
• head and neck cancer
• head and neck pathology
• immunosuppression
• oropharyngeal carcinoma
• squamous cell carcinoma
• superficial brachytherapy

Collision carcinoma is rare in clinical practice, especially in the head and neck region. In this paper, we report a case of squamous cell carcinoma (SCC) and neuroendocrine carcinoma (NEC) colliding in the larynx and review 12 cases of collision carcinoma in the head and neck to further understand collision carcinoma, including its definition, diagnosis, and treatment.

A 61-year-old man presented with a 1-year history of hoarseness. Contrast-enhanced magnetic resonance imaging of the larynx revealed that the right vocal cord had a nodule-like thickening with obvious enhancement. Laryngoscopy revealed a neoplasm on the right vocal cord, and a malignant tumor was initially considered. A frozen section of right vocal cord was performed under general anesthesia. The pathological result showed a malignant tumor in the right vocal cord. The tumor was excised with a CO₂ laser (V_c type). Routine postoperative pathology showed moderately differentiated SCC with small cell NEC in the right vocal cord. No metastatic lymph nodes or distant metastases were found on postoperative positron emission tomography/computed tomography. Because of the coexistence of SCC and NEC, the patient received adjuvant chemotherapy and radiotherapy. The patient was followed for 8 mo, and no recurrence or distant metastasis was found.

The treatment of collision carcinoma in the head and neck region is uncertain due to the small number of cases.

• Collision carcinoma
• Neuroendocrine carcinoma
• Squamous cell carcinoma
• Head and neck
• Larynx
• Case report