Synchronous Schwannoma and Gastrointestinal Stromal Tumor in Small Intestine – A Rare Case

Introduction/Objective

Small bowel Schwannoma is a benign neoplasm of nerve sheath cells. The Gastrointestinal stromal tumor (GIST) constitutes only about 1-2% of small bowel spindle cell tumors. The simultaneous presence of two tumors in the small bowel is extremely uncommon.

Methods/Case Report

We report a case of small bowel GIST co-existing with Schwannoma. A 64-year-old female with a known history of Neurofibromatosis was admitted for excision of a small bowel tumor. MRI of the abdomen revealed two enhancing lesions in the left upper quadrant adjacent to the small bowel. Differential considerations included GIST versus Neurofibroma. Left hemicolectomy with small bowel resection was performed. The proximal small bowel revealed GIST, spindle cell type, low risk (3.5 cm), low grade (<5 mitoses/ 5mm2). Tumor cells were diffusely reactive to CD34, CD117, and DOG1 immunostains and were nonreactive to S100 and SOX10 immunostains confirming the diagnosis of GIST. Another segment of the small bowel revealed a 1.5 cm well-circumscribed, predominantly spindle cell tumor with abundant myxoid stroma and prominent cyst formation. Tumor cells were diffusely reactive to S100 and SOX10 immunostains but nonreactive to CD34, CD117, and DOG1, favoring a diagnosis of Schwannoma. Gastrointestinal Schwannomas may be associated with Neurofibromatosis in some cases. GIST, a KIT- or PGDFRA-signaling driven mesenchymal tumor has also rarely been reported to be associated with Neurofibromatosis type 1. However, synchronous small bowel Schwannoma and GIST represent a rare co-existence of two different histopathologic subtypes of spindle cell tumors.

Results (if a Case Study enter NA)

NA

Conclusion

In summary, we present the rare co-existence of two different spindle cell lesions in Neurofibromatosis patient.

High-Grade Sarcoma Arising in the Background of Growing Teratoma Syndrome; A Rare Case

Introduction/Objective

Growing teratoma syndrome is a rare condition seen in patients with a history of immature teratomas or mixed germ cell tumor status post-treatment. It usually occurs within the first two years of diagnosis but rarely can be seen years later.

Methods/Case Report

We report a case of a 48-year-old female with a previous history of ovarian malignancy in adolescence status post-TAH/BSO and chemotherapy, now presenting with a 23 cm multi cystic septate mass with some solid components in the subdiaphragmatic area, extending into the liver on imaging. Nodular implants along the surface of the right hepatic lobe and multiple peritoneal implants were seen. Histology of peritoneal implants showed fibro adipose tissue admixed with rare scattered glandular elements, epithelial fragments, and mature neuroglial tissue, consistent with mature teratoma. Liver biopsy revealed short fascicles of spindled, epithelioid and rhabdoid tumor cells admixed with foci of the myxoid stroma. Scattered moderate cytologic atypia, atypical mitosis, and necrosis were appreciated. Tumor cells showed strong and diffuse reactivity to vimentin while being negative for epithelial, neural/mesenchymal, mesothelial, sex cord-stromal, and germ cell differentiation markers. Differential diagnostic considerations included spindle cell transformation of a germ cell tumor or high-grade sarcoma, not otherwise specified arising in the background of growing teratoma syndrome. FISH testing for isochromosome 12p was negative excluding sarcomatoid germ cell tumor.

Results (if a Case Study enter NA)

NA

Conclusion

This case study highlights the importance of considering the rare complication of high-grade sarcoma arising in the background of growing teratoma syndrome.