Collision tumor of the stomach: gastric adenocarcinoma intermixed with gastrointestinal stromal tumor

Synchronous occurrence of gastric cancer and gastrointestinal stromal tumor: A case report and review of the literature

BACKGROUND

To evaluate the clinicopathological features and prognosis of gastric cancer (GC) occurring synchronously with gastrointestinal stromal tumor (GIST).

CASE SUMMARY

We report 19 patients with concurrent GC and GIST (17 male and 2 female, median age 62 years). GC was most often located in the lower third of the stomach. GIST was diagnosed preoperatively in four patients. GIST was most often located in the gastric body (n = 8, 42%). The most common growth pattern in GIST was extraluminal (n = 12, 63%). The positive expression rates of CD117 and CD34 in GIST were 100% and 95%, respectively. Most patients with GIST (n = 17, 89%) were very low or low risk. There was no recurrence of GIST during follow-up. The 3-year cumulative survival rate was 73.9%, and the 5-year cumulative survival rate was 59.2%. The combined analysis of this study and literature reports (47 reports, 157 patients) found that GC and GIST were usually located in the lower third (42%) and middle third (51%) of the stomach. GC was usually early (stage I: 42%), poorly differentiated (42%) intestinal-type adenocarcinoma (51%). GISTs were primarily small in diameter (median: 1.2 cm) and very low or low risk (89%).

CONCLUSION

Synchronous GC and GIST may not be rare. They have specific clinicopathological characteristics, and may have mutual inhibition in pathogenesis and progression.

Benign Neurofibroma/Schwannoma Hybrid Peripheral Nerve Sheath Tumor of the Ulnar Nerve Harboring a Metastatic Papillary Thyroid Carcinoma Deposit: A Case Report of Tumor-to-Tumor Metastasis

A 74-year-old man with a medical history significant for papillary thyroid cancer (PTC) presented with a rapidly enlarging grape-sized mass in his right medial arm with paresthesia in the ulnar nerve distribution. Imaging was suspicious for a peripheral nerve sheath tumor (PNST), but an ultrasound-guided biopsy was equivocal. The mass was excised with final histopathology demonstrating a benign neurofibroma/schwannoma hybrid nerve sheath tumor (N/S HNST) harboring a metastatic PTC deposit, ultimately mimicking the rare glandular schwannoma subtype. Next-generation sequencing (NGS) of the lesion demonstrated somatic variants in BRAF and TERT (common in PTC) and NF2 (common in PNSTs). After excision, the patient's nerve symptoms improved. A postsurgical PET/CT scan also showed progression in the lungs/mediastinum. Due to the metastatic nature of his PTC, he was treated with 14 mg of Lenvima (lenvatinib) daily, and his PET/CT surveillance was performed at more frequent intervals. Tumor-to-tumor metastasis (TTM) is a rare occurrence. To our knowledge, this is the first case reported on PTC metastasizing into a benign (hybrid) PNST, which mimicked glandular schwannoma. Symptomatology, imaging characteristics, NGS, and histopathological characteristics that can decipher between different benign PNST subtypes (schwannoma, neurofibroma, glandular, hybrid, etc.), malignant PNSTs (MPNSTs), and TTM are described.

Preoperatively diagnosed gastric collision tumor with mixed adenocarcinoma and gastrointestinal stromal tumor: a case report and literature review

Reports of gastric collision tumors, comprising adenocarcinoma and gastrointestinal stromal tumor, are extremely rare. Here, we report the case of a 68-year-old male who was diagnosed with a lower-body, moderately differentiated, tubular-type adenocarcinoma and submucosal tumor and underwent an elective D2 distal gastrectomy. The tumor cells of the gastrointestinal stromal tumor were positive for H-caldesmon and CD117, weakly positive for smooth muscle actin and DOG-1, and negative for desmin, S-100 protein, CD31, and AE1/AE3. The tumor had grown into a mixed form of adenocarcinoma and gastrointestinal stromal tumor. Thus, we report the first case of a preoperatively diagnosed collision tumor in the stomach consisting of adenocarcinoma and gastrointestinal stromal tumor.

Collision Tumor of Adenocarcinoma and Gastrointestinal Stromal Tumor in the Small Bowel

We report a very rare case of collision tumor composed of primary adenocarcinoma of the jejunum and gastrointestinal stromal tumor (GIST). The patient was a 63-year-old man who visited our hospital for epigastralgia and vomiting. Abdominal computed tomography revealed a mass in the upper jejunum, with gastric and duodenal dilatation. Endoscopy of the small bowel showed a circumferential tumor in the upper jejunum, which was diagnosed as primary adenocarcinoma by tissue biopsy. Thereafter, partial resection of the small bowel from the third part of the duodenum over the upper jejunum was performed. A tumor colliding with the primary adenocarcinoma was identified on the serosal side of the jejunum in the excised specimen and was histologically diagnosed as GIST. The annual incidence of primary adenocarcinoma of the small bowel (i.e., jejunum and ileum excluding the duodenum) has been reported to be 7 in 1 million people, and only 6 cases of collision tumor of the small bowel (i.e., duodenum: 5, ileum: 1) have been reported thus far. Although esophageal, gastric, and large intestinal collision tumors composed of primary cancer and GIST have been reported, to our knowledge, the present patient is the first case of the small bowel. The cause of or correlation between 2 tumors forming a collision tumor remains unclear. In the present patient, there was no pathological finding of infiltration between the 2 tumors. Although the collision of the 2 tumors was unclear, the findings indicate their independent development in closely located regions consistent with collision tumors.

Coexistence of gastrointestinal stromal tumor and inflammatory myofibroblastic tumor of the stomach presenting as a collision tumor: first case report and literature review

Collision tumors of the stomach are rare. We report on a case of a collision tumor consisting of a gastrointestinal stromal tumor (GIST) and an inflammatory myofibroblastic tumor (IMT) of the stomach in a 16-year-old female. A polypoid mass located in the distal body of the stomach was observed on abdominal computed tomography. Laparoscopic wedge resection of the stomach and 4d lymph node biopsy was performed. On gross examination, a protruding submucosal mass, measuring 4 × 3.5 × 2.5 cm in size, was detected. Histological examination showed two distinct GIST and IMT component presenting a collision tumor. The small nodular area, composed of CD117-positive spindle cells, was typical of GIST, and the adjacent larger area, composed of myofibroblastic spindle cells with prominent chronic inflammatory cells infiltrate, mainly lymphocytes and plasma cells, had a characteristic appearance of IMT. The 4d lymph node showed metastatic inflammatory myofibroblastic tumor. To the best of our knowledge, this is the first case of a collision tumor consisting of a GIST and an IMT arising in the stomach.

Gastric collision tumors: an insight into their origin and clinical significance

Collision tumors are rare neoplasms displaying two distinct cell populations developing in juxtaposition to one another without areas of intermingling. They are rare entities with only 63 cases described in English literature. Tumors encountered are gastric adenocarcinomas colliding with lymphomas, gastrointestinal stromal tumors, squamous cell carcinomas, and neuroendocrine tumors. Their cell origin is obsolete by the time of diagnosis. Different tumorigenesis theories have been suggested to explain their behavior, yet none has managed to provide satisfactory explanation for all cases. Clinically they are indistinguishable from the dominant tumor. Lack of data does not allow detailed assessment of their behavior yet they seem aggressive neoplasms with dismal prognosis. The majority of cases have been diagnosed postoperatively during histologic examination of specimens. There are no guidelines or concrete evidence to support best way of adjuvant or other types of treatment. However, these rare neoplasms might help in unlocking secrets of cancer behavior including tumorigenesis, differentiation, and adhesion and thus clinicians should be aware of their existence.

Metastatic melanoma with striking adenocarcinomatous differentiation illustrating phenotypic plasticity in melanoma

We report on the highly unusual case of a 75-year-old woman who developed a biphasic right axillary mass of apparent melanoma and adenocarcinoma 13 years after a diagnosis of primary melanoma on her right upper back. The differential diagnosis included a collision tumor and metastatic melanoma with adenocarcinomatous transdifferentiation. We utilized immunohistochemical staining, DNA sequencing, and comparative genomic hybridization (CGH) to characterize this unusual tumor. By immunohistochemistry, the melanomatous component was positive for S100 and Melan-A, and had patchy positivity for cytokeratin. The adenocarcinomatous component was negative for melanoma markers, but was strongly positive for cytokeratin. In addition, the glandular component was positive for CDX-2 and Ber-EP4, giving the distinct histologic and immunohistochemical impression of a gastrointestinal metastasis nested within a deposit of metastatic melanoma. Clinical and radiologic workup failed to reveal a primary gastrointestinal malignancy. Molecular genetic analysis, including DNA sequencing and CGH, revealed that both areas contained an identical NRAS Q61K mutation and had highly similar CGH profiles, including gains of chromosome 1q and losses of 1p, 4, 9, and 10, which are archetypical of melanoma. The NRAS mutation was also identified in a deposit of metastatic melanoma resected 12 years earlier, but was not seen in the patient's nontumorous tissue, indicating that it was somatically acquired. Genetic analyses demonstrate that 2 morphologically distinct tumors arose from a common ancestor melanoma cell that harbored an NRAS mutation and subsequently divergently evolved by the acquisition of additional genomic alterations. Our findings illustrate the ability of molecular analyses to resolve lineage in complex neoplasms and illustrate the phenotypic plasticity of cancer cells.

Composite adenocarcinoma and carcinoid gastric tumor in chronic atrophic gastritis and pernicious anemia

A 42-year-old Hispanic female was referred for investigation of unexplained weight loss. Initial upper endoscopy showed atrophic gastritis. Repeat endoscopy one year later revealed the presence of mixed composite tumor consisting of gastric adenocarcinoma and carcinoid tumors. Treatment was accomplished by surgical excision. Such cases are extremely rare and few such reports are available in the literature. We discuss the pathologies and means by which these tumors are classified and treated.

Laparoscopic wedge resection of synchronous gastric intraepithelial neoplasia and stromal tumor: A case report

Synchronous occurrence of epithelial neoplasia and gastrointestinal stromal tumor (GIST) in the stomach is uncommon. Only rare cases have been reported in the literature. We present here a 60-year-old female case of synchronous occurrence of gastric high-level intraepithelial neoplasia and GIST with the features of 22 similar cases and detailed information reported in the English-language literature summarized. In the present patient, epithelial neoplasia and GIST were removed en bloc by laparoscopic wedge resection. To the best of our knowledge, this is the first reported case treated by laparoscopic wedge resection.