Collision tumors: A review of their types, pathogenesis, and diagnostic challenges

Molecular subtypes of neuroendocrine carcinomas: A cross-tissue classification framework based on five transcriptional regulators

Neuroendocrine carcinomas (NECs) are extremely lethal malignancies that can arise at almost any anatomic site. Characterization of NECs is hindered by their rarity and significant inter- and intra-tissue heterogeneity. Herein, through an integrative analysis of over 1,000 NECs originating from 31 various tissues, we reveal their tissue-independent convergence and further unveil molecular divergence driven by distinct transcriptional regulators. Pan-tissue NECs are therefore categorized into five intrinsic subtypes defined by ASCL1, NEUROD1, HNF4A, POU2F3, and YAP1. A comprehensive portrait of these subtypes is depicted, highlighting subtype-specific transcriptional programs, genomic alterations, evolution trajectories, therapeutic vulnerabilities, and clinicopathological presentations. Notably, the newly discovered HNF4A-dominated subtype-H exhibits a gastrointestinal-like signature, wild-type RB1, unique neuroendocrine differentiation, poor chemotherapeutic response, and prevalent large-cell morphology. The proposal of uniform classification paradigm illuminates transcriptional basis of NEC heterogeneity and bridges the gap across different lineages and cytomorphological variants, in which context-dependent prevalence of subtypes underlies their phenotypic disparities.

Simultaneous primary thyroid MALT lymphoma and papillary thyroid cancer

The mucosa-associated lymphoid tissue (MALT) lymphoma subtype, specifically extranodal marginal zone B-cell lymphoma, is a rare variant. Within this subtype, primary thyroid MALT lymphoma is an uncommon occurrence. The literature provides limited documentation on thyroid MALT lymphomas, as their prevalence is comparatively lower than in other organ sites. The coexistence of papillary thyroid carcinoma (PTC) and thyroid MALT lymphomas is exceedingly rare. It presents a rare case of primary thyroid MALT lymphoma accompanied by PTC, thyroid lymphoma not being considered before surgery. A 64-year-old female patient, who had been experiencing symptoms related to a substantial thyroid tumor for a duration of three years, she refused to do a needle biopsy before surgery and expressed a preference for surgical resection. Consequently, the patient underwent a total thyroidectomy along with lymphadenectomy of the central compartment. A histological examination subsequently confirmed the presence of papillary thyroid carcinoma (PTC) and mucosa-associated lymphoid tissue (MALT) lymphoma. Due to the favorable response of the MALT lymphoma to local treatment and the absence of metastasis in other organs, no further treatment was administered for the MALT lymphoma following the surgery. Currently, the patient exhibits no signs of tumor recurrence based on ultrasound and laboratory evaluations. We also provide an overview of the clinical findings on PTC and MALT lymphoma patients already reported and discuss the possible treatment strategy.

Malignant glomus tumor arising in association with a fumarate hydratase-deficient leiomyoma: An unusual collision tumor

Collision tumors, defined as "two independent neoplasms that occur in close proximity to one another but maintain distinct boundaries," are quite rare. We report an exceptional collision tumor composed of a genetically confirmed malignant glomus tumor and a fumarate hydratase (FH)-deficient leiomyoma, presenting as a subcutaneous thigh mass in a 38-year-old male who was known to have hereditary leiomyomatosis and renal cell carcinoma syndrome. Microscopic examination identified a biphasic subcutaneous mass comprising sheets and nodules of glomus cells, with nuclear atypia and mitotic activity, and fascicles of mitotically inactive smooth muscle with variably pleomorphic nuclei and intracytoplasmic eosinophilic inclusions, features of FH-deficient leiomyoma. Immunohistochemistry demonstrated loss of FH and robust 2-succinocysteine expression in the smooth muscle, with a normal (FH-retained) expression pattern in the glomus tumor. Next-generation sequencing, performed on the glomus tumor component, identified CARMN::NOTCH2 fusion, characteristic of malignant glomus tumors. Awareness of the distinctive morphologic, immunohistochemical, and molecular genetic features of glomus tumors and FH-deficient leiomyomas is important for correct clinical management of patients with exceptional collision tumors of this type.

A Rare Case of a Primary Cutaneous Collision Tumor Comprising Malignant Melanoma and Rhabdomyosarcoma

This case reports a 35-year-old man who presented with a painful erythematous nodule on his right posterior calf. He first noticed this nodule several years ago and it often bled upon contact with clothing. An excisional biopsy of the skin lesion revealed two distinct populations of cells. One population of epithelioid cells stained positive for Mart-1, HMB45, and SOX-10, confirming the diagnosis of malignant melanoma. The second population of cells stained positive for desmin and calponin, confirming the diagnosis of sarcoma with muscular differentiation. Subsequently, these unusual findings led to the diagnosis of a collision tumor comprising malignant melanoma and rhabdomyosarcoma. Follow-up PET/CT and brain MRI revealed no metastasis from the primary skin lesion. This case highlights a rare combination of cell types found within a collision tumor in addition to providing details on how to diagnose this skin lesion.

Synchronous Papillary and Follicular Carcinoma with Scalp and Nodal Metastasis: A case report with review of literature

Collision tumor comprise of existence of two histologically distinct and separate neoplasms in any organ. Thyroid gland is an uncommon site for these tumors, with frequently involved organs being liver, adrenal and stomach. Even among the synchronous tumors of thyroid, papillary and medullary carcinoma are most commonly reported. The present case reports a rare presentation of a collision tumor comprising of papillary and follicular carcinoma with scalp metastasis from the follicular carcinoma and lymph nodal metastasis from the papillary component. It is essential for the clinician to be aware of such an entity so as to guide further treatment and management.

[Collision tumours in skin: usually an incidental finding. A retrospective study with literature revision]

A collision tumour (CT) is a neoplastic lesion comprised of two or more distinct cell populations that maintain distinct borders. Mostly, these are incidental findings in skin biopsies, whose pathologic mechanism and prevalence remain unknown, with few references among literature. Here, we present a retrospective study of CT, diagnosed by a dermatopathologist in our hospital between 2019-2022. Lesions have been defined individually and organized into three categories: benign-benign (BB), benign-malignant (BM) and malignant-malignant (MM). A total of 108 CT were diagnosed (1,4% of the biopsies from the dermatopathologist during this period), from which BM was the most frequent collision (48,5%). Globally, basal cell carcinoma (BCC) was the main malignant lesion and melanocytic nevus (MN) the main benign lesion. We have used the software Stata 14.2 in order to analyse results, and we have detected a statistically significant difference between age and collision type.

Collision Tumors of the Colon and Peritoneum: Signet-Ring Cell Carcinoma and Granular Cell Tumor

Collision tumors, although rare, characterized by two distinctive (morphological, as well immunohistochemical) and spatially independent tumor components at the same location, are always puzzling for clinicians, pathologists, and patients because they do not fit into the usual approaches, being neither diagnostic nor therapeutic. Reviewing the specialized literature, to date, collision tumors have been reported in multiple locations such as the skin, esophagus, stomach, intestine, liver, kidney, bladder, adrenal gland, or thyroid. We report a case of coexistence at the same site of a malignant tumor of the ascending colon and a benign tumor emerging from the peritoneal lining, initially thought by the surgeon to be right-sided serosal carcinomatosis. But histopathological examination reveals that those multiple serosal nodules were benign granular cell tumors that have collided with highly aggressive transparietal signet-ring colon carcinoma. These results put the patient's prognosis and therapeutic strategy in a different light than the clinical and intraoperative evaluation.

Use of Dermatoscopy in Lesions Suspicious for Melanoma: Two Case Reports

Abstract is missing (Short communication)

Thyroid collision tumour with pulmonary metastases treated effectively with nedaplatin and paclitaxel chemotherapy: A case report

Collision tumour of the thyroid is a rare entity for which surgical resection is the primary treatment. We present here a case of a collision thyroid tumour of oncocytic and papillary carcinoma with lung metastases occurring in a 62-year-old woman who initially presented with a rapidly enlarging cervical mass and dyspnoea. The patient had extensive venous tumour thrombosis in the internal jugular and subclavian veins. The patient received six cycles of combined chemotherapy with nedaplatin and paclitaxel which significantly reduced the size of the metastases in the lungs. Following discharge from the hospital, the patient was treated with oral anlotinib and at 14 months follow up she had not experienced any serious side effects and the metastases in her lung and thyroid surgery areas were well controlled.

Uterine collision tumor. Case report and review of the literature

Objectives

To report the case of a patient with a uterine collision tumor and to conduct a review of the literature.

Material and methods

A 76-year-old patient who presented to the national cancer referral center in Bogota (Colombia), where she was diagnosed with a uterine collision tumor consisting of a seroustype endometrial adenocarcinoma and a cervical adenosarcoma. The patient underwent surgical treatment followed by chemotherapy and supplemental radiotherapy, and died 16 months later. A search was conducted in the Medline via PubMed and Embase databases, including reports and case series of women with a diagnosis of uterine collision tumor, with retrieval of information regarding diagnosis, treatment and prognosis. A narrative summary of the findings was made.

Results

The search identified 36 titles, of which 14 studies with 17 patients were included. The most frequent histopathological diagnosis was endometrial adenocarcinoma and high and low grade endometrial sarcoma (47 %). Primary treatment was surgery and adjuvant treatment with chemotherapy and radiotherapy (15 %) was performed in close to 50 % of cases. One-year survival was 75 %.

Conclusions

No cases of uterine collision tumors with the histopathology or in the location of the reported case were found in the literature. If this reported case is taken into account, 2-year mortality is 28 %. Further studies to describe the immunohistochemistry, treatment and prognosis of this condition are needed.

A collision tumor of nasopharyngeal carcinoma and primary mantle cell lymphoma in the nasopharynx: a case report and review of the literature

BACKGROUND

Nasopharyngeal carcinoma (NPC) is more common in men aged 40 to 59, and radiotherapy is an effective treatment. Nasopharyngeal lymphoma (NPL) is rare, and the coexistence of nasopharyngeal mantle cell lymphoma (MCL) and NPC is even rarer. A collision tumor is a rare type of tumor that refers to two or more different tumors occurring in the same organ. No reports to date have described a collision tumor of NPC and MCL occurring within the same nasopharyngeal mass. We herein report the successful treatment of a unique case of synchronous coexistence of NPC and MCL occurring in the nasopharynx of a Chinese man.

CASE PRESENTATION

A 58-year-old man presented with a 5-month history of swallowing discomfort. Biopsy was performed under nasopharyngeal endoscopy, and histopathology revealed NPC. Magnetic resonance imaging revealed lesions in the nasopharynx, oropharynx, and tonsils, as well as enlarged lymph nodes in the parotid gland, posterior ear, and neck. This may be a synchronous dual primary tumor coexisting with NPC and NPL. Pathology consultation confirmed that the biopsy specimen of the nasopharynx was a collision tumor of NPC and MCL. Positron emission tomography computed tomography (PET-CT) revealed thickening of the posterior wall of the nasopharynx, which was considered NPC with lymphoma. The enlargement of the pharyngeal lymph ring and multiple hypermetabolic lymph nodes were evaluated as lymphoma infiltration. The patient received two courses of R-CHOP chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) followed by head and neck radiotherapy. At the time of this writing, he had remained alive without recurrence for 61 months since the initial treatment and was still undergoing follow-up.

CONCLUSIONS

It is very important to correctly recognize collision tumors. Magnetic resonance imaging helps identify different components of collision tumors. Pathological examination helps to confirm the diagnosis. Histological examination reveals different components, and PET-CT can help determine the extent of the lesion. Dose-adjusted chemotherapy combined with radiotherapy may have promising herapeutic effects, but additional case studies are needed to confirm.

Collision tumor of a papillary and follicular thyroid carcinoma: a case report

BACKGROUND

Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) are common differentiated thyroid cancers, but the detection of a collision tumor is an extremely rare event.

CASE PRESENTATION

The patient was a 69-year-old Japanese female with multiple cervical lymph node swellings and a thyroid tumor. Preoperative fine needle aspiration cytology of the enlarged lymph node revealed a cytological diagnosis of papillary thyroid carcinoma (PTC). A total thyroidectomy, right cervical dissection and paratracheal dissection were performed. Histopathological and immunohistochemical analyses of resected specimens revealed a collision tumor of PTC and FTC. Multiple metastases of papillary carcinoma were found in the dissected lymph nodes. In the PTC lesion, IHC for BRAF (V600E) was positive but negative for the FTC lesion. Genetic analyses further revealed a TERT promoter C228T mutation in PTC and a NRAS codon 61 mutation in FTC. The patient died of recurrent cancer 8 months after surgery.

CONCLUSIONS

A case of a collision tumor of PTC and FTC is very rare, and even fewer cases have been subjected to genetic scrutiny. The present case was successfully diagnosed by pathological examination using immunohistochemical and genetic analyses. The TERT promoter mutation in the PTC lesion was consistent with the aggressive behavior of the cancer.

Collision Tumor of the Ovary Involving Sertoli-Leydig Cell Tumor and High-Grade Serous Carcinoma-Report of the First Case

We report a collision tumor in the ovary of a 60-yr-old woman composed of high-grade serous carcinoma and Sertoli-Leydig cell tumor. Collision tumors in the ovary are rare and to the best of our knowledge, combination of ovarian high-grade serous carcinoma and Sertoli-Leydig cell tumor has not been described before.

Renal Oncocytoma and Pelvic Urothelial Carcinoma in a Nephrectomy Specimen of a 72-Year-Old Patient

We present the case of a 72-year-old gentleman who presented with a left renal mass. His Computerized Tomography Angiogram showed an 11.8 x 11.3 cm mass involving the upper pole of the left kidney. The mass showed a central stellate scar. There was no locoregional lymphadenopathy. His radical nephrectomy specimen was received in our lab. Sectioning showed a large tumor in the upper pole with a central stellate scar. Microscopically, it showed sheets and nests of round cells with eosinophilic cytoplasm and round nuclei. It was positive for CD117 and negative for CK7. The sections from the renal pelvis showed a urothelial carcinoma arising from the urothelial lining and infiltrating the muscular wall of the renal pelvis. This tumor was positive for CK7 and GATA3. In this case report, we present a rare collision tumor of renal oncocytoma and pelvic urothelial carcinoma.

Case Report: The first case of primary pulmonary collision tumor comprising mixed squamous cell and glandular papilloma and glomus tumor

A collision tumor is a rare entity, particularly if occurring in the lung. We report a case of a 57-year-old woman with a primary pulmonary collision tumor comprising mixed squamous cell and glandular papilloma (MSGP) and glomus tumor (GT). An abnormal mass was discovered in the right lung by computed tomography (CT) of the chest. A right lower lobectomy with mediastinal lymph node dissection was performed. Histological examination of the surgical specimen suggested that the lung cancer was composed of two neoplastic components. To the best of our knowledge, this is the first report of a primary pulmonary collision tumor comprising two benign tumors of different origins, which were MSGP and GT.

Cutaneous Malignant Squamomelanocytic Tumor: A Case Report of a Rare Neoplasm

ABSTRACT

Cutaneous squamomelanocytic tumor (SMT) is an exceedingly rare cutaneous malignancy characterized by the presence of both squamous cell carcinoma and malignant melanoma within a single tumor. SMT typically presents clinically as keratotic skin papulonodules, most commonly occurring on the face, scalp, or other sun-exposed areas of middle-aged to elderly White male patients. Owing to the rare nature of this tumor, the histogenesis and prognosis remain relatively unclear. Histopathological examination of the tangential biopsy revealed an invasive cutaneous malignancy consisting of 2 distinct yet closely associated atypical cell populations: (1) a population of atypical squamoid epithelial cells arranged in cords and keratin pearls and (2) a population consisting of atypical, spindled cells with fine melanin pigment arranged in confluent sheets. Both populations of atypical cells emanated in an invasive pattern from the underside of the overlying epidermis into the deep dermis. Squamomelanocytic tumors are among the rarer types of collision tumors between 2 malignant lesions as most are basomelanocytic. For most reported SMTs, the melanoma population comprises epithelioid cell morphology, whereas our tumor is composed of spindled cell morphology. In this article, we exemplify a unique case of SMT in an 87-year-old male patient.

Primary malignant melanoma of the bladder collides with high-grade non-invasive urothelial papillary carcinoma: A case report

The present study reported a case of primary malignant melanoma of the bladder colliding with high-grade non-invasive urothelial papillary carcinoma with clinical, pathologic and immunohistochemical analysis, and reviewed the relevant literature. A 74-year-old male presented with hematuria; B ultrasound and computed tomography revealed a solid mass in the bladder and transurethral resection of the bladder lesion was performed. Microscopically, the tumors were composed of morphologically diverse malignant melanomas (95%) and high-grade non-invasive urothelial papillary carcinoma (5%), with no closely related or transitional regions. Immunohistochemistry indicated that malignant melanoma cells expressed HMB45, Melan-A and S-100, whereas they did not express any epithelial markers. The urothelial carcinomas expressed broad-spectrum cytokeratin and GATA3, and were negative for melanoma markers. The diagnosis of collision tumor between primary malignant melanoma of bladder and high-grade non-invasive urothelial papillary carcinoma depends on clinical and pathological examinations; this pathology is prone to recurrence and metastasis and has a poor prognosis.

Case report: Tumor collision in the colon, adenocarcinoma – lymphoma

Introduction

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

Presentation of case

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.

Discussion

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.

Conclusion

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.

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It is a rare entity often diagnosed in surgery or by the pathologist

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Collision tumors pose a challenge in determining the prognosis of the patient

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As collision tumors are composed of two different tumors, the recommended treatment is to target the most aggressive neoplasm.

Thyroid collision tumors; A case series with literature review

Background

Collision tumors are two histologically distinct types of malignancies within the same mass and organ. The aim of this study is to present a case series of thyroid collisions.

Methods

This was a multicenter retrospective case series study. The participants were consecutive in order. Socio-demographic and clinical data were obtained from hospital records.

Results

The study included eight cases comprising six (75%) females and two (25%) males. The patients had different presentations, including neck swelling, dyspnea, and dizziness. The pathology was successfully determined through fine-needle aspiration. Four patients (50%) underwent lobectomy, whereas the other half (four patients) underwent total thyroidectomy.

Conclusion

Collision tumors of papillary thyroid cancer (PTC) and follicular thyroid carcinoma (FTA) or medullary thyroid carcinoma (MTC) and FTA are exceedingly rare phenomena that most commonly affect females. Complete or partial thyroidectomy is the ideal management of choice for these cases and is associated with good survival.

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Collision tumors are two distinct types of malignancies with dissimilar cellular lineages and genetic origins within the same mass.

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Patients with thyroid collision tumors have rarely been observed in the literature.

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Most thyroid collision tumors consisting of papillary and medullary carcinoma.

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In this study, several cases of thyroid collision tumors have been discussed.

Clinicopathological and Molecular Features of Secondary Cancer (Metastasis) to the Thyroid and Advances in Management

Secondary tumours to the thyroid gland are uncommon and often incidentally discovered on imaging. Symptomatic patients often present with a neck mass. Collision tumours of secondary tumours and primary thyroid neoplasms do occur. Ultrasound-guided fine-needle aspiration, core-needle biopsy, and surgical resection with histological and immunohistochemical analysis are employed to confirm diagnosis as well as for applying molecular studies to identify candidates for targeted therapy. Biopsy at the metastatic site can identify mutations (such as EGFR, K-Ras, VHL) and translocations (such as EML4-ALK fusion) important in planning target therapies. Patients with advanced-stage primary cancers, widespread dissemination, or unknown primary origin often have a poor prognosis. Those with isolated metastasis to the thyroid have better survival outcomes and are more likely to undergo thyroid resection. Systemic therapies, such as chemotherapy and hormonal therapy, are often used as adjuvant treatment post-operatively or in patients with disseminated disease. New targeted therapies, such as tyrosine kinase inhibitors and immune checkpoint inhibitors, have shown success in reported cases. A tailored treatment plan based on primary tumour features, overall cancer burden, and co-morbidities is imperative. To conclude, secondary cancer to the thyroid is uncommon, and awareness of the updates on diagnosis and management is needed.

Collision of Basal Cell Carcinoma and Sebaceous Carcinoma Extirpated With Mohs Micrographic Surgery

Collision tumors are neoplasms composed of two or more distinct cellular lineages coexisting at the same anatomic site. Incomplete biopsy, partial pathological slide examination or failure to include this diagnosis into the clinical differential may complicate and delay appropriate therapy. Although collision tumors are well documented, basal cell carcinoma (BCC) occurring with sebaceous carcinoma (SC) has only been reported in a single case report. The aim of the authors is to present a case of collision BCC and SC to highlight a rare clinicopathological case. We also present this case to advise caution to detect mimickers of BCC that warrant greater clinical workup and use this case to emphasize the importance of Mohs micrographic surgery for the treatment of SC.

Renal Tumors with Oncocytic and Papillary Features: A Phenotypic and Genotypic Study

The occurrence of kidney oncocytic lesions with an admixed papillary component is not unusual in routine pathology practice. These neoplasms with dual morphology are classically recognized as collision tumors with variable malignant potential. Using immunohistochemistry, we investigated fluorescent in situ hybridization and next generation sequencing of the genetic and phenotypic profiles in the two components of 11 kidney tumors with colliding oncocytic and papillary features. The oncocytic component was CD117 positive, CK7 negative, and AMACR negative; the papillary component was CK7 positive, AMACR positive, and CD117 negative in all cases. Fluorescence in situ hybridization (FISH) results were inconsistent. Next generation sequencing (NGS) analysis demonstrated that the mutations identified in the two tumor components were identical and displayed an allelic frequency of approximately 50%, strongly suspicious for genetic polymorphisms. The two oncocytic and papillary tumor counterparts shared the same genetic profile and did not harbor pathogenic mutations. Clinical confirmation of the biological benign features of these tumors is required. The term collision tumor is not suitable for these neoplasms, and we propose the term oncopapillary tumor for this histological entity.