Programmed death-ligand (PD-L) 1 and 2 are ligands of programmed cell death 1 (PD-1) receptor. They are members of the B7/CD28 ligand-receptor family and the most investigated inhibitory immune checkpoints at present. PD-L1 is the main effector in PD-1-reliant immunosuppression, as the PD-1/PD-L pathway is a key regulator for T-cell activation. Activation of T-cells warrants the upregulation of PD-1 and production of cytokines which also upregulate PD-L1 expression, creating a positive feedback mechanism that has an important role in the prevention of tissue destruction and development of autoimmunity. In the context of inadequate immune response, the prolonged antigen stimulation leads to chronic PD-1 upregulation and T-cell exhaustion. In lung cancer patients, PD-L1 expression levels have been of special interest since patients with non-small cell lung cancer (NSCLC) demonstrate higher levels of expression and tend to respond more favorably to the evolving PD-1 and PD-L1 inhibitors. The Food and Drug Administration (FDA) has approved the PD-1 inhibitor, pembrolizumab, alone as front-line single-agent therapy instead of chemotherapy in patients with NSCLC and PD-L1 ≥1% expression and chemoimmunotherapy regimens are available for lower stage disease. The National Comprehensive Cancer Network (NCCN) guidelines also delineate treatment by low and high expression of PD-L1 in NSCLC. Thus, studying PD-L1 overexpression levels in the different histological subtypes of lung cancer can affect our approach to treating these patients. There is an evolving role of immunotherapy in the other sub-types of lung cancer, especially small cell lung cancer (SCLC). In addition, within the NSCLC category, squamous cell carcinomas and non-G12C KRAS mutant NSCLC have no specific targetable therapies to date. Therefore, assessment of the PD-L1 expression level among these subtypes of lung cancer is required, since lung cancer is one of the few malignances wherein PD-L1 expression levels is so crucial in determining the role of immunotherapy. In this study, we compared PD-L1 expression in lung cancer according to the histological subtype of the tumor.

Introduction: Celiac disease (CD) is an immune-mediated disease caused by ingesting gluten-containing foods and is characterized mainly by malabsorptive diarrhea. Furthermore, distinguishing between mild disease and asymptomatic individuals is critical and necessitates a high level of clinical suspicion. Short stature, delayed puberty, bone abnormalities, neurological problems, and intestinal cancer can all be consequences of a delayed diagnosis. This study aimed to determine the prevalence of celiac disease among our community's recurrent diarrhea patients. Methods: This was a cross-sectional study aimed at determining the frequency of celiac disease in patients with chronic diarrhea. One hundred eighty-eight patients between the ages of 18 and 60 years who had chronic diarrhea lasting greater than three months were enrolled in this study. Stratification was utilized to control for modifiers. A p-value of ≤ 0.05 was considered significant. Results: A total of 74.5% of patients (n=140) were male, while 25.5% (n=48) were female with a mean age of 38.48±10.85 years. The average duration of celiac disease symptoms was 8.17± 3.75 months. Celiac disease was found in 12.2% (n=23) of the individuals. Also, 21% of individuals with a positive family history of CD devolved CD, compared to those without prior CD family history (p=0.01). Conclusions: In individuals with chronic diarrhea for more than three months, the prevalence of celiac disease was determined to be 12.2% (n=23). There was a statistically significant difference between those with a positive family history of CD and those who did not have the condition.

Ameloblastic fibro-odontoma (AFO) is a relatively rare, benign noninvasive mixed odontogenic neoplasm derived from epithelial and ectomesenchymal elements of the dental tissues. It usually presents with a mean age of 11.5 years and in the posterior segment of the mandible. It is extremely rare in the posterior maxilla. Although the latest WHO edition classified AFO as developing odontoma, here we present a locally aggressive AFO in a 21-year-old male involving the posterior maxilla and sinus with bone destruction. The patient presents with a two-year history of slowly progressive left facial swelling with malodorous drainage. The CT scan revealed a 5.5 x 4.3 cm well-circumscribed expansile mass with mixed attenuation and peripheral calcification occupying the left maxilla and sinus with bone destruction of the hard palate and orbital rim. According to the literature, most of the AFO cases were treated adequately through a conservative approach with just enucleation or surgical curettage. To our knowledge, our case is the first case treated aggressively with left maxillectomy, palatectomy, and reconstruction surgery because of its radiologic findings, which suggested a locally invasive neoplasm. Histologically, the specimen showed a mixture of proliferative epithelial, mesenchymal tissue elements, and variable amounts of mineralized deposits consisting of enamel matrix and dentinoid deposits, and the final diagnosis was AFO. In conclusion, we present a rare case of AFO with an unusual aggressive presentation, age group, and site involved. The radiographic, histopathologic features, and therapeutic approaches of this unusual locally aggressive tumor are presented with the review of relevant literature.

Chordoma is a rare malignant neoplasm derived from notochordal tissue that primarily affects the axial skeleton. Almost 40% of patients have non-cranial chordoma metastases. The most common metastatic sites are the lungs, bones, lymph nodes, and subcutaneous tissue. We present a 52-year female with a history of sacral chordoma presenting with abdominal fullness, early satiety, and a palpable abdominal mass. Abdominal magnetic resonance imaging (MRI) revealed an isolated, highly vascularized, and multilobed liver mass in the left lateral segment. The mass was surgically removed using a clean surgical margin. A histological examination and immunohistochemical staining were consistent with a metastatic chordoma. Two years later, follow-up imaging studies showed a 6.5 × 4.0 × 2.0 cm right liver lesion with multiple lungs, chest wall, pleural, and diaphragmatic lesions. Microscopic- and immunohistochemical staining revealed a recurrent metastatic chordoma. Herein, we present a unique case of metastatic recurrent chordoma in the liver with the involvement of other sites. To the best of our knowledge, no other case of recurrent liver metastasis has been reported.

An arteriovenous malformation (AVM) is a vascular lesion most frequently encountered in the brain, lungs, colon, and soft tissues of the extremities. However, rarely, an AVM may develop in the uterus, where it can cause abnormal and even life-threatening uterine bleeding. Here, we present the case of a 41-year-old G6P6 woman with abnormal uterine bleeding which resulted in a hemoglobin level of 10.2 g/dL. On gross examination, the uterus was enlarged measuring 17.5 cm x 12.0 cm x 10.0 cm, with a pronounced globoid appearance and bogginess on palpation. The cut surface was hemorrhagic and notable for numerous tortuous dilated spaces of variable sizes. These hemorrhagic, cavernous spaces were grossly apparent throughout the entire myometrium, but were found to be most prominent in the lower uterine segment of the anterior wall. Microscopic examination revealed an admixture of malformed vasculature comprising arteries, venules, and capillaries. The vessels showed prominent dilation and tortuosity with abrupt variation in the thickness of the media and elastic lamina, as highlighted by Von Gieson stain. Unlike in many other organ systems where AVMs are often considered congenital lesions, uterine AVMs are more often acquired lesions that develop following iatrogenic uterine trauma, namely cesarean section or curettage. Upon review of our patient’s history, her final delivery was via cesarean section, after which she developed abnormal uterine bleeding. We present this case as a reminder to consider uterine AVM in cases of abnormal uterine bleeding, as it may be easily overlooked by even the most experienced pathologist.

The prognosis of cutaneous melanoma (CM) is based on the histological characteristics of the primary tumor, such as Breslow depth, ulceration, and mitotic rate. The lymph node ratio (LNR) is the ratio of the involved lymph nodes (LNs) divided by the total number of LNs removed during regional LN dissection. LNR is a prognostic factor for many solid tumors; however, controversies exist regarding CM. This study sought to analyze the role of LNR as a prognostic factor in CM. An extensive literature search was conducted using PubMed, Google Scholar, Medline, and the Cochrane Central Registry of Controlled Trials from January 1966 to July 2015. The keywords included in the search were CM and inclusion of the ratio of positive to the total number of LNs as a prognostic factor. The outcomes analyzed included the number of patients with positive LNs, type of survival analysis, and results from the multivariate analysis. A total of 11 studies involving 12,011 patients with positive LNs were evaluated. No previous randomized controlled trials, meta-analyses, or systematic reviews were identified in the Cochrane database on the prognostic value of LNR in CM. The primary electronic database search resulted in 333 full-text articles. The LN location examined was the cervical, axillary, and inguinal regions in all studies except for one that examined only the inguinal region. All studies except three studied the prognostic value of the LNR as a categorical variable rather than a continuous variable. LNR was categorized as A (<= 0.1), B (0.11-0.25), and C (>0.25). All studies identified LNR as an independent predictor of overall survival (OS), disease-free survival (DFS), or disease-specific survival (DSS). The hazard ratio (HR) and confidence interval (CI) associated with either DFS or OS were available only in a few studies. Moreover, pooled HR for OS was 2.08 (95% CI: 1.48 2.92), for DFS was 1.364 (95% CI: 0.92-2.02), and for DSS was 1.643 (95% CI: 0.89-3.0). The LNR provides superior prognostic stratification among patients with CM. Additional adequately powered prospective studies are needed to further define the role of LNR and be included in the staging system of CM and direct adjuvant therapy.