Hepatic metastasis with heterologous rhabdomyoblastic differentiation in a patient with gastrointestinal stromal tumor treated with imatinib.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the intestinal tract. In patients with locally advanced and/or metastatic GIST, the introduction of tyrosine kinase inhibitor, imatinib mesylate, has transformed the management of this previously untreatable neoplasm into a treatable entity. Approximately 80% of advanced metastatic GISTs respond to imatinib treatment. However, the majority of patients suffer disease progression at a median of 2 years due to drug resistance. Generally progressing GISTs retain their typical morphology. Herein, we report an extremely rare case of progressive metastatic GIST with heterologous rhabdomyoblastic differentiation after, imatinib mesylate treatment. We also review the relevant literature.

Pigmented hepatocellular adenoma with complete CD34 immunostaining pattern: A diagnostic dilemma.

WHO defines hepatocellular adenoma (HCA) as a benign tumor composed of cells closely resembling normal hepatocytes, which are arranged in plates separated by sinusoids. It is more common in women. The present concerns a 41 years female who was found to have a mass lesion in liver on ultrasound while undergoing routine evaluation for dyspepsia. Computed tomography scan of abdomen showed 10 × 8 cm lesion in liver. Extended left hepatectomy was performed. Grossly hepatic cut surface showed circumscribed tumor with dark gray or black color. Microscopy revealed hepatocellular adenoma with abundant Dubin Johnson like pigment deposition. CD34 immunostaining showed complete sinusoidal pattern. We labeled the tumor as pigmented hepatic adenoma with complete CD34 staining pattern. To the best of author's knowledge only eight cases of pigmented hepatocellular adenoma are described in world literature.

Mycophenolate mofetil-induced colitis with graft versus host disease-like features in a liver transplant recipient.

Mycophenolate mofetil (MMF) is a commonly used immunosuppressive drug in the management of transplant recipients. Gastrointestinal (GI) toxicity (diarrhea) is the most frequently reported adverse event in MMF-treated transplant patients. MMF-induced Graft versus Host Disease has rarely been reported in literature. We report a case of MMF-induced colitis with Graft versus Host Disease-like features, to highlight the importance of high clinical suspicion for its diagnosis, and that appropriate management in such a setting can reduce morbidity and mortality. We also review the relevant literature.

Hepatic solitary fibrous tumor: Report of a rare case.

Solitary fibrous tumor (SFT) of the liver is an extremely rare neoplasm of mesenchymal origin. In the English literature, less than 40 cases of SFTs of the liver have been reported. The present case concerns a 34-year-old female who presented to us with complaint of dyspepsia. On examination, there was hepatomegaly. On ultrasound examination, an SOL in the liver was detected. Large tumor measuring 14.5 × 10 × 8 cm was resected. Microscopic evaluation of the tumor showed a well-circumscribed, low to moderately cellular tumor demonstrating spindle- and fibroblast-like cells within the collagenous stroma. Immunohistochemistry revealed diffuse strong cytoplasmic immunopositivity of CD34, Bcl2, and vimentin. A diagnosis of a benign SFT was given. The patient remained well 4 years after surgery. SFT is a rare mesenchymal neoplasm that occasionally involves the liver in adult patients. Most SFTs are benign, but some may have malignant histological features. With less than 40 reported cases in the literature, little can be said regarding its natural history or the benefits of adjuvant radio chemotherapy. Complete surgical resection remains the cornerstone of its treatment.

Gastrointestinal stromal tumors: a clinicopathological and immunohistochemical study of 121 cases.

Background Primary mesenchymal tumors of the gastrointestinal tract are a heterogeneous group of tumors with a wide clinical spectrum, of which gastrointestinal stromal tumors (GIST) typically occur in middle-aged to older individuals. This study evaluated the clinicopathological and morphological features of GIST of the intestinal tract. Methods The study included 108 gastrointestinal and 13 extra-gastrointestinal stromal tumors involving the mesentry and retroperitoneum between January 1989 and July 2007. Immunohistochemical expression of CD117, CD34, SMA, Desmin, S100, and Ki-67 were studied. Results GIST comprised 108 of 120 (90%) of the mesenchymal tumors. The tumor was located in the stomach in the majority (55%) of patients followed by small intestine (30%), retroperitoneum (7%) and the colorectum (4%). There was a significant correlation between tumor size and mitotic index, with larger tumors having higher mitotic index (p<0.001). Mitotic index per 5 mm2 correlated with high cellularity (p<0.001), presence of necrosis (p<0.001) and presence of mucosal invasion (p=0.01). Expression of CD117 was seen in 94%, CD34 in 59%, SMA in 41%, S-100 in 33%, and desmin in 4% of tumors. Conclusion We found GIST to be the most common mesenchymal tumor of the gastrointestinal tract.