Small Cell Lung Carcinoma and Synchronous Rectal Adenocarcinoma and Jejunal Gastrointestinal Stromal Tumor Present in a Patient With History of Laryngeal Squamous Cell Carcinoma

Discussion

The incidences of distant metastases of primary laryngeal squamous cell carcinoma were reported as 3.7 to 16% (5). Our patient had a history of laryngeal carcinoma for 20 years with no detailed information of the location within his larynx. Interestingly, at 20 years follow up post chemoradiation therapy, no recurrent laryngeal carcinoma or regional metastasis was identified. However, three additional masses were incidentally identified in the lung, rectum, and jejunum, respectively. Through multidisciplinary tumor board discussion, three biopsies were performed and confirmed synchronous SCLC, rectal adenocarcinoma and jejunal gastrointestinal stromal tumor. To the best of our knowledge, cases of synchronous primary rectal adenocarcinoma, SCLC and jejunal gastrointestinal stromal tumor have not been documented in the English literature through a PubMed search.

Due to the significant differences in tumor morphology of each entities, biopsies with histological assessment are the key to the correct diagnoses. Clinicians and pathologists need to be aware that one or multiple other primary tumors can be seen during a regular follow up of cancer after therapy. In our case, the incidentally identified 1.3 cm nodule in the lung was cytologically and histologically evaluated through CT-guided fine needle aspiration and biopsy. Different to the metastatic squamous cell carcinoma of the larynx, the tumor had a rosetting appearance consisting of small cells with scant cytoplasm, ill-defined cell borders, finely granular nuclear chromatin, with absent or inconspicuous nucleoli. The tumor cells are positive for the neuroendocrine markers including synaptophysin and chromogranin, and positive for TTF1 making the primary lung neuroendocrine carcinoma. The available predictive models for colorectal carcinoma are based on the evaluation of symptoms, and their diagnostic accuracy is limited (3). The diagnosis of rectal adenocarcinoma in our case is mainly based on colonoscopy and biopsy. Metastatic carcinoma is commonly seen in a jejunal mass in adult patients with a history of carcinoma, but our CT imaging findings were more consistent with a neuroendocrine tumor than metastatic carcinoma. However, the morphology of the jejunal mass showed cytologically bland spindle cell proliferation with positive GIST markers including DOG1 and CD117, supporting the diagnosis of GIST (pT2N0), which is consistent with a separate primary tumor.

This is an unusual case, and the treatment is even more challenging. On its own, the SCLC is a highly fatal cancer, the combination of platinum and etoposide with thoracic radiation therapy being the most widely used regimen, with clinical trials consistently achieving median survivals of 18 to 24 months and 40% to 50% 2-year survival rates with less than a 3% treatment-related mortality (6). Colorectal carcinomas (CRC) have a more favorable prognosis, the five-year survival rate of stage IIIB CRC is 72% (7). Lastly, GIST is the most common mesenchymal tumor in the jejunum and at stage I, resection alone is an effective treatment. Through multidisciplinary discussions, the patient underwent FSRT, an effective treatment options for SCLC, in combination with chemotherapy with platinum and etoposide to control the SCLC and then, he underwent laparoscopic resection of the jejunal GIST and rectal cancer. At 8 months follow up postsurgery, the patient was doing well and no significant tumor recurrence was identified on CT images.

In summary, this report documents a rare and unusual case of synchronous primary SCLC, rectal adenocarcinoma and jejunal GIST incidentally identified in a 67-year-old male with previous history of laryngeal squamous cell carcinoma during the regular follow up. Sequential treatment with FSRT and chemotherapy prior to resection of the rectal carcinoma and GIST provided the patient individualized medical care. Overall, this case demonstrates the importance of identifying unique primary malignancies despite the relatively low incidence of occurrence in patients with a history of cancer, as the therapeutic approach and potential patient outcomes can be drastically impacted.