Gastrointestinal stromal tumors. A clinicopathological study

OBJECTIVES

To evaluate the clinical presentations and immunohistochemical (IHC) properties of gastrointestinal stromal tumors (GISTs) and to compare them to internationally published data.

METHODS

Thirty-six patients diagnosed with GISTs between January 1997 and December 2015 were retrospectively studied in 2 tertiary hospitals. Immunohistochemical staining was carried out prospectively when it has not been completed fully at the beginning. Results: The median age of patients was 54 years  (range; 17-81 years). Predominantly, we found more females were affected. The male to female ratio was 1:1.7. The most frequently affected organs were the stomach (63.8%) followed by small bowel (25%) and colorectal region (8.4%). Abdominal pain was the most frequent presentation in 33.3% of the patients then gastrointestinal (GI) bleeding in 30.5%. Most of the gastric GISTs were at early stages at presentation: stage 1 and II (60.8%), while in non-gastric GISTs, the tumor stage was advanced: stage III and IV (69.3%). The IHC characteristic of GIST in descending order showed positivity for vimentin (88.9%), CD117 (83.3%), CD34 (77.8%), Ki67 (63.9%), SMA (38.9%), desmin (27.8%), and S100 (19.4%).

CONCLUSION

Gastrointestinal stromal tumors in our study demonstrates a major similar feature as the published international data. However, minor differences do exist in terms of clinical features and immunohistochemistry.

Biological alterations in renal and hepatic tissues by a novel gold (III) anti-cancerous compound

Objective(s):

Newer organo-metallic, specifically gold (III) complexes with multiple ligands are currently being formulated with primary focus of having increased anti-cancerous properties and decreased cytotoxicity. In this study, histological toxicity profile of a newly formulated anti-cancerous gold (III) compound [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) was investigated by evaluation of kidney and liver tissues of rats treated by the compound.

Materials and Methods:

This is a quasi-experimental study. In acute toxicity component of the study, (n = 16) male rats weighing between 200–250 g were administered single, variable concentration of the gold (III) compound, [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) to determine LD₅₀ (dose that is lethal to 50% of rats). An IP injection of 2.3 mg/kg (equivalent to 1/10 of LD₅₀) was injected for 14 consecutive days to (n=10) male rats in the sub-acute component of the study. Autopsy preservation of liver and kidney tissue in buffered formalin, sample processing, histopathological evaluation, and comparison with unremarkable controls (n=5) was conducted sequentially.

Results:

A dose of 2.3 mg/kg did not produce any tubular necrosis in kidney specimens. Mild interstitial inflammation with prominence of plasma cells was the main histological alteration. Plasmacytic pyelitis was also seen. Varying extents of cytoplasmic vacuolization and mild focal lobular and portal inflammation were predominant hepatic microscopic findings.

Conclusion:

[trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) produced no histological damage in renal and hepatic tissues of rats. This very limited sample animal-based study points to the relative safety of this new gold compound. However, there is a need to compare this compound with established drugs in a comparative non-animal based study.

Malignant gastrointestinal neuroectodermal tumor: a case report and review of the literature

BACKGROUND

Malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare entity that was first described by Zambrano et al. in 2003 as "Clear cell sarcoma-like tumor of the gastrointestinal tract". It shares some of the histological features of clear cell sarcoma (CCS) but lacks the immunohistochemical reactivity for melanocytic markers. We report a case of GNET that was initially misdiagnosed as gastrointestinal stromal tumor (GIST). Recognizing this entity is important to avoid misdiagnosis.

CASE PRESENTATION

A case of an 18-year-old male presented with a small intestinal tumor. Histologically it was characterized by polygonal cells arranged in pseudoalveolar pattern and situated in the muscularis propria. Scattered osteoclast-like multinucleated giant cells were also noted. The neoplastic cells were positive for S-100 protein and negative for HMB-45, Melan A, smooth muscle actin, desmin and CD117. EWSR1 gene rearrangement was detected by fluorescence in situ hybridization (FISH) analysis. The patient returned with recurrence after 36 months' management by surgical resection and died one year later.

CONCLUSIONS

GNET can be mistaken histologically for other non-epithelial gastrointestinal tumors. Awareness of its existence and diagnostic criteria by the pathologist is necessary to avoid misdiagnosis, particularly as GIST, CCS or malignant peripheral nerve sheath tumor (MPNST).

Primary gastric actinomycosis: report of a case diagnosed in a gastroscopic biopsy

Background

Primary gastric actinomycosis is extremely rare, the appendix and ileocecal region being the most commonly involved sites in abdominopelvic actinomycosis. Herein, we report a case of primary gastric actinomycosis. The diagnosis was made on microscopic evaluation of gastroscopic biopsy specimens. To the best of our knowledge, this is the third case to be reported in the literature, in which the diagnosis was made in a gastroscopic biopsy rather than a resection specimen.

Case presentation

An 87-year-old Saudi male on medication for cardiomyopathy, premature ventricular contractions, renal impairment, hypertension, and dyslipidemia, presented to the emergency department with acute diffuse abdominal pain, abdominal distension, constipation and vomiting for two days, with no history of fever, abdominal surgery or trauma. The patient was admitted to the hospital with an impression of gastric outlet obstruction. Based on radiologic and gastroscopic findings, a non-infectious etiology was suspected, possibly adenocarcinoma or lymphoma. Gastroscopic biopsies showed an actively inflamed, focally ulcerated atrophic fundic mucosa along with fragments of a fibrinopurulent exudate containing brownish, iron negative pigment and abundant filamentous bacteria, morphologically consistent with Actinomyces.

Conclusion

Althuogh extremely rare, primary gastric actinomycosis should be considered in the differential diagnosis of radiologic and gastroscopic diffuse gastric wall thickening and submucosal tumor-like or infiltrative lesions, particularly in patients with history of abdominal surgery or trauma, or those receiving extensive medication. A high level of suspicion is required by the pathologist to achieve diagnosis in gastroscopic biopsies. Subtle changes such as the presence of a pigmented inflammatory exudate should alert the pathologist to perform appropriate special stains to reveal the causative organism.

Novel KRAS gene mutations in sporadic colorectal cancer

Introduction

In this article, we report 7 novel KRAS gene mutations discovered while retrospectively studying the prevalence and pattern of KRAS mutations in cancerous tissue obtained from 56 Saudi sporadic colorectal cancer patients from the Eastern Province.

Methods

Genomic DNA was extracted from formalin-fixed, paraffin-embedded cancerous and noncancerous colorectal tissues. Successful and specific PCR products were then bi-directionally sequenced to detect exon 4 mutations while Mutector II Detection Kits were used for identifying mutations in codons 12, 13 and 61. The functional impact of the novel mutations was assessed using bioinformatics tools and molecular modeling.

Results

KRAS gene mutations were detected in the cancer tissue of 24 cases (42.85%). Of these, 11 had exon 4 mutations (19.64%). They harbored 8 different mutations all of which except two altered the KRAS protein amino acid sequence and all except one were novel as revealed by COSMIC database. The detected novel mutations were found to be somatic. One mutation is predicted to be benign. The remaining mutations are predicted to cause substantial changes in the protein structure. Of these, the Q150X nonsense mutation is the second truncating mutation to be reported in colorectal cancer in the literature.

Conclusions

Our discovery of novel exon 4 KRAS mutations that are, so far, unique to Saudi colorectal cancer patients may be attributed to environmental factors and/or racial/ethnic variations due to genetic differences. Alternatively, it may be related to paucity of clinical studies on mutations other than those in codons 12, 13, 61 and 146. Further KRAS testing on a large number of patients of various ethnicities, particularly beyond the most common hotspot alleles in exons 2 and 3 is needed to assess the prevalence and explore the exact prognostic and predictive significance of the discovered novel mutations as well as their possible role in colorectal carcinogenesis.

Histological changes in kidney and liver of rats due to gold (III) compound [Au(en)Cl(2)]Cl

Introduction

Development of novel metallodrugs with enhanced anti-proliferative potential and reduced toxicity has become the prime focus of the evolving medicinal chemistry. In this regards, gold (III) complexes with various ligands are being extensively investigated. In the current study renal and hepatic toxicity of a newly developed gold (III) compound [Au(en)Cl₂]Cl was assessed by histopathological evaluation of liver and kidney specimens of rats exposed to the compound.

Methods

Male rats (n = 42) weighing 200–250 gram were injected single, varying doses of gold (III) compound [(dichlorido(ethylenediamine)aurate((III)]chloride [Au(en)Cl₂]Cl in the acute toxicity component of the study. In the sub-acute toxicity part, a dose of 32.2 mg/kg (equivalent to 1/10 of LD50) was administered intraperitoneally for 14 consecutive days before sacrificing the animals. After autopsy, the renal and hepatic tissues were preserved in buffered formalin. Processing of the samples was followed by histopathological evaluation. The results were compared with the normal controls (n = 11).

Results

A dose of 32.2 mg/kg (1/10 of LD₅₀) revealed no renal tubular necrosis. The predominant histopathological finding was mild pyelitis, a prominence of eosinophils and mild congestion. The hepatic lesions comprised varying extents of ballooning degeneration with accompanying congestion and focal portal inflammation.

Conclusion

Gold (III) compound [Au(en)Cl₂]Cl causes minimal histological changes in kidney and liver of rats, reflecting its relative safety as compared to other clinically established antineoplastic drugs.

Atherosclerosis in sickle cell disease - a review

Acute, vaso-occlusive crises are the most common and earliest clinical manifestations of sickle cell disease. Recent thoughts about development of atherosclerosis as a result of this disease are presented. Current insights into the pathogenesis of atherosclerosis in sickle cell disease are reviewed, in particular the role of endothelial dysfunction, homocysteine and platelets. Common and uncommon sites of atherosclerosis are described. Radiological assessment and potential therapeutic agents to slow the progression of atherosclerosis are discussed. Finally, treatment of atherosclerosis in certain sites is evaluated and reviewed.

Very low prevalence of epidermal growth factor receptor (EGFR) protein expression and gene amplification in Saudi breast cancer patients

BACKGROUND

Breast cancers which demonstrate EGFR protein expression, gene amplification and/or gene mutations may benefit therapeutically from tyrosine kinase inhibitors. In Western studies, EGFR protein expression has been demonstrated in 7-36% of breast cancer patients, while gene amplification has been found in around 6% of cases and mutations were either absent or extremely rare. Studies addressing EGFR protein expression and gene amplification in Saudi breast cancer patients are extremely scanty and the results reported have been mostly non-conclusive. Herein we report the prevalence of EGFR protein expression and gene amplification in a cohort of Saudi breast cancer patients.

FINDINGS

We noticed a remarkably low incidence of EGFR protein expression (1.3%) while analyzing the spectrum of molecular subtypes of breast cancer in a Saudi population by immunohistochemistry. Also, EGFR gene amplification could not be demonstrated in any of 231 cases studied using silver enhanced in situ hybridization.

CONCLUSIONS

The extremely low incidence of EGFR protein expression and gene amplification in Saudi breast cancer patients as compared to Western populations is most probably ethnically related as supported by our previous finding in the same cohort of a spectrum of molecular breast cancer types that is unique to the Saudi population and in stark contrast with Western and other regionally based studies. Further support to this view is provided by earlier studies from Saudi Arabia that have similarly shown variability in molecular breast cancer subtype distribution between Saudi and Caucasian populations as well as a predominance of the high-grade pathway in breast cancer development in Middle East women. More studies on EGFR in breast cancer are needed from different regions of Saudi Arabia before our assumption can be confirmed, however.

Protein expression profile and prevalence pattern of the molecular classes of breast cancer--a Saudi population based study

BACKGROUND

Breast cancer is not a single entity but a diverse group of entities. Advances in gene expression profiling and immunohistochemistry as its surrogate marker have led to the unmasking of new breast cancer molecular subtypes, resulting in the emergence of more elaborate classification systems that are therapeutically and prognostically more predictive. Molecular class distribution across various ethnic groups may also reveal variations that can lead to different clinical outcomes in different populations.

METHODS

We aimed to analyze the spectrum of molecular subtypes present in the Saudi population. ER, PR, HER2, EGFR and CK5/6 were used as surrogate markers for gene expression profiling to classify 231 breast cancer specimens. Correlation of each molecular class with Ki-67 proliferation index, p53 mutation status, histologic type and grade of the tumor was also carried out.

RESULTS

Out of 231 cases 9 (3.9%) were classified as luminal A (strong ER +ve, PR +ve or -ve), 37 (16%) as luminal B (weak to moderate ER +ve, and/or PR +ve), 40 (17.3%) as HER2+ (strong or moderately positive HER 2 with confirmation by silver enhanced in-situ hybridization) and 23 (10%) as basal (CK5/6 or EGFR +ve). Co-positivity of different markers in varied patterns was seen in 23 (10%) of cases which were grouped into a hybrid category comprising luminal B-HER2, HER2-basal and luminal-basal hybrids. Ninety nine (42.8%) of the tumors were negative for all five immunohistochemical markers and were labelled as unclassified (penta negative). A high Ki-67 proliferation index was seen in basal (p=0.007) followed by HER2+ class. Overexpression of p53 was predominantly seen in HER2+(p=0.001) followed by the basal group of tumors. A strong correlation was noted between invasive lobular carcinoma and hormone receptor expression with 8 out of 9 lobular carcinoma cases (88.9%) classifiable as luminal cancers. Otherwise, there was no association between the molecular class and the histologic type or grade of the tumor.

CONCLUSIONS

Subtyping by use of this immunohistochemical panel revealed a prevalence pattern that is unique to our population; luminal tumors comprised only 19.9%, and the unclassified group (penta negative) 42.8%, a distribution which is distinctive to our population and in contrast with all Western studies. The presence of a predominant unclassified group also suggests that the currently used molecular analytic spectrum may not completely encompass all molecular classes and there is a need to further refine and develop the existing classification systems.

Distribution of molecular breast cancer subtypes in middle eastern-saudi arabian women: a pilot study

Increasing evidence suggests the possibility of relevant molecular differences between cancers from different ethnic groups. This study uses gene expression profiling by quantitative real time polymerase chain reaction (qRT-PCR) to identify "intrinsic" subtypes in a Saudi population of breast cancers and compares the distribution of subtypes to the more commonly profiled Caucasian population. In addition, the immunohistochemical profile of breast cancers was correlated to the gene expression analysis. Discrepancy rate of 39% in subtype prediction between gene expression and immunohistochemical profile of the tumors was noticed. Most of this variation was in the luminal subtype. Frequency of HER2+ subtype in the Saudi cases was high (28%) by both the immunohistochemistry (IHC) and the qRT-PCR classification. Triple-negative tumors comprised 39% while only 11% showed a basal-like profile. Analysis of larger cohort of patients is needed to determine the molecular taxonomy of breast cancer in the Saudi population and the benefits from the diagnostic classification developed in the West.

Mixed vestibular schwannoma and meningioma without neurofibromatosis

The co-existence of meningioma and schwannoma as 2 distinct histologic components within the same tumor has been described in neurofibromatosis 2 (NF2), but the co-existence of both tumors without evidence of NF2 is much rarer. Here, we are reporting a case of mixed schwannoma with meningioma without clinical evidence of NF2. In an adult Saudi lady with progressive left-sided hearing loss, left cerebellopontine tumor was diagnosed by MRI, and the histopathological diagnosis revealed that this tumor was composed of vestibular schwannoma and meningioma. This case is discussed with literature review.