Unusual Case of Multiple Synchronous Gastrointestinal Stromal Tumors of the Jejunum Presenting as an Arteriovenous Malformation

Introduction/Objective

Gastrointestinal stromal tumor (GIST) arises from the interstitial cell of Cajal. 30% of GISTs arise in the jejunum. GISTS are generally solitary although multiple GISTs may be synchronous or metachronous. There are a few reports of a GIST of the jejunum mimicking a vascular malformation/arteriovenous malformation (AVM) prior to surgical excision.

Methods

Herein, we report a case of four synchronous GISTs of jejunum. One GIST, highly vascularized, presented with lower gastrointestinal bleeding. The patient was a 40-year-old female presenting with epigastric pain and melena.

Results

She was found to have an ulcerated lesion in the distal jejunum by capsule enteroscopy and double balloon enteroscopy, interpreted as an arteriovenous malformation and tattooed. Several other non-ulcerated “polyps” were described. Gross examination of the ensuing segmental resection of jejunum demonstrated four bosselated tumors ranging from 3.1 cm to 6.5 cm. Microscopically, three tumors did not extend to the surface of the jejunum and were predominantly composed of spindle cells. One tumor (identified by tattoo) extended to the surface with ulceration. This tumor was dominated by wide vascular channels with a spindle cell component between the channels. The four tumors were each positive for CD117, DOG1, and Succinate dehydrogenase B (SDH), identifying the four tumors as non-SDH-deficient GISTs. Ki-67 proliferation index was less than 5% in all four masses.

Conclusion

Multiple GISTs are rare, classified as either sporadic or familial. Familial GEISTs are described in neurofibromatosis type 1, Carney’s triad and Carney-Stratakis syndrome. Pediatric GISTs, with clinical and genetic features often differing from typical adult tumors may also be multiple. Our patient’s four GISTs are considered multiple synchronous sporadic neoplasms. This case serves as an important reminder for pathologists consider GIST in the evaluation of a highly vascular gastrointestinal proliferation and keep in mind the possibility of multiplicity.

SMARCA4 Deficient Thoracic Sarcoma Presenting with a Pathologic Fracture of Proximal Tibia and L5 Vertebral Body: a Case Report and Review of Literature

Introduction/Objective

SMARCA4 (BRG1) is a central component of the Switch/Sucrose-Non-Fermentable (SWI/SNF) chromatin remodeling complex which plays a critical role in the initiation, progression and dedifferentiation of a variety of cancers arising in different anatomical sites. The recently discovered SMARCA4-deficient thoracic sarcoma (DTS) can present as a mediastinal, pleural or pulmonary mass and constitutes a unique and highly lethal entity.

Methods

Here we present an interesting case of a 66-year-old, smoker male with past medical history of COPD, polysubstance abuse, hepatitis C virus, and alcoholic cirrhosis who presented with left proximal tibia pathological fracture, L5 vertebral body lytic lesion, left leg cellulitis and hypercalcemia. Imaging studies, tibia biopsy, thoracocentesis, histopathological examination, and immunohistochemical stains were performed.

Results

Imaging studies revealed a 3.1 cm, right upper lobe speculated lung mass along with multiple other lung nodules. Numerous arterially enhancing hepatic masses up to 2.8 cm were also identified. The patient underwent intramedullary nail, cementation and tibia biopsy followed by thoracentesis a month later.The histological sections revealed sheets of poorly differentiated malignant epithelioid cells showing high nuclear pleomorphism, prominent nucleoli, eosinophilc cytoplasm with extensive necrosis, and high mitosis (Ki-67 around 100%). The tumor cells lacked the expression of SMARCA4 (BRG1), cytokeratin, SALL4, CD34, TTF-1, P40, S100, HMB45, pan melanoma, desmin, CD31, ERG, CD30, CD56, chromogranin, CD38, CD45, CD3, ALK-1, myeloperoxidase, glypican-3, hepatocyte, and inhibin with mixed kappa and lambda. Tumor cells expressed SATB2 and focal synaptophysin, consistent with SMARCA4 deficient thoracic sarcoma metastasizing to the bone. The patient’s condition rapidly deteriorated and he died within two months.

Conclusion

An accurate diagnosis of these tumors is paramount and can be challenging. However, recognizing SMARCA4-DTS from other types of epithelioid tumors that involve the thoracic region is clinically relevant, as targeted therapies for SMARC-deficient tumors are currently being investigated and new clinical trial data show therapeutic benefit.

Prometastatic CXCR4 and Histone Methyltransferase EZH2 are Upregulated in SMARCB1/INI1-deficient and TP53-mutated Metastatic Poorly Differentiated Chordoma to the Liver

Introduction/Objective

Chordoma is a rare tumor most commonly arising in the sacrococcygeal region from notochord remnants. Usually, these tumors are locally invasive and recurrent, but do not have the capability to metastasize. A newly described aggressive variant called poorly differentiated chordoma is different than conventional chordoma in that it does not have the well-differentiated histologic appearance of conventional chordoma and also exhibits loss of SMARCB1/INI1.

Methods

Herein, we describe a case of poorly differentiated chordoma with SMARCB1/INI1 loss, concurrent TP53 mutation and Rb1 loss.

Results

The patient is a 55-year-old man with a history of a previously resected sacrococcygeal chordoma, who was found to have new hepatic, lung, and adrenal lesions. Biopsy of the liver showed sheets of malignant epithelioid cells with vacuolated cytoplasm, areas of necrosis, and up to 5 mitoses in one high power field. No physaliferous features or matrix material were seen. After an extensive panel of immunohistochemical markers, the origin of the metastatic tumor could not be determined and the tumor was only positive for Cam5.2, EMA, and CD56. Brachyury was performed due to the patient’s previous history and was positive. Genomic testing showed a SMARCB1 mutation, a TP53 mutation, and RB1 loss. Additional markers were performed and the tumor showed a Ki-67 proliferation index of approximately 80%, mutant p53 protein, loss of INI1, and strong expression of prometastatic CXCR4 and the histone methyltransferase EZH2. The most recent follow-up of the patient showed that the patient was receiving palliative care.

Conclusion

Poorly differentiated chordoma is a highly aggressive variant of chordoma with few cases reported. This case of SMARCB1/INI-deficient, poorly differentiated chordoma also showed concurrent TP53 mutation and loss of RB1, which resulted in malignant transformation with loss of differentiation, cell cycle progression, up-regulation of prometastatic CXCR4 and the histone methyltransferase EZH2 causing aggressive behavior and metastasis.