Primary Gastric and Duodenal Mucosa-Associated Lymphoid Tissue Lymphoma With Symptomatic Anemia.

Mucosal-associated lymphoid tissue (MALT) is a low-grade lymphoma derived from marginal zone B cells in extranodal tissue. Gastric MALT lymphoma is frequently seen; however, duodenal MALT lymphoma is rare, and there is no standardized knowledge up to date about the management of the disease. We present a case of a 56-year-old woman with gastric and duodenal MALT lymphoma.

The 1000 Mitoses Project: A Consensus-Based International Collaborative Study on Mitotic Figures Classification.

Introduction. The identification of mitotic figures is essential for the diagnosis, grading, and classification of various different tumors. Despite its importance, there is a paucity of literature reporting the consistency in interpreting mitotic figures among pathologists. This study leverages publicly accessible datasets and social media to recruit an international group of pathologists to score an image database of more than 1000 mitotic figures collectively. Materials and Methods. Pathologists were instructed to randomly select a digital slide from The Cancer Genome Atlas (TCGA) datasets and annotate 10-20 mitotic figures within a 2 mm2 area. The first 1010 submitted mitotic figures were used to create an image dataset, with each figure transformed into an individual tile at 40x magnification. The dataset was redistributed to all pathologists to review and determine whether each tile constituted a mitotic figure. Results. Overall pathologists had a median agreement rate of 80.2% (range 42.0%-95.7%). Individual mitotic figure tiles had a median agreement rate of 87.1% and a fair inter-rater agreement across all tiles (kappa = 0.284). Mitotic figures in prometaphase had lower percentage agreement rates compared to other phases of mitosis. Conclusion. This dataset stands as the largest international consensus study for mitotic figures to date and can be utilized as a training set for future studies. The agreement range reflects a spectrum of criteria that pathologists use to decide what constitutes a mitotic figure, which may have potential implications in tumor diagnostics and clinical management.

Misdiagnosed Pityriasis Rubra Pilaris Successfully Managed With Isotretinoin: A Case Series.

Being a rare inflammatory, hyperproliferative dermatosis, diagnosing pityriasis rubra pilaris (PRP) can be a challenge to many clinicians. Our case reports aim to demonstrate that PRP is frequently diagnosed and managed as atopic dermatitis (AD) and that distinguishing features on dermoscopy, and biopsy can help diagnose this rare disease. The study also aims to show that PRP can be successfully treated with Isotretinoin. Our case series aims to describe two cases of PRP, initially diagnosed as AD and managed with topical corticosteroids. Being the first case series in the literature to describe the incidences of diagnosing PRP as AD portrays the significance of utilizing dermoscopy and biopsy as tools to confirm this diagnosis for appropriate management. Although PRP is a rare diagnosis, dermoscopy and biopsy can help confirm the disease. Management with isotretinoin will most likely have successful outcomes in those patients.

INI-1-Deficient Sinonasal Carcinoma: Case Report with Emphasis on Differential Diagnosis.

SMARCB1-deficient sinonasal carcinoma is a newly described entity, with less than 100 reported cases. It is characterized by basaloid or rhabdoid morphology and is diagnosed by complete loss of nuclear SMARCB1 (INI-1). The morphologic appearance, specific immunophenotypic markers, and unique molecular make-up distinguish this entity from other various malignant neoplasms. We present a case of a 55-year-old male that presented with a large progressing palatine mass. Magnetic resonance imaging showed a heterogeneous mass involving the left maxillary space. The initial biopsy was diagnosed as undifferentiated carcinoma. Resection was performed, and immunohistochemical studies revealed a complete loss of INI-1, refining the diagnosis to SMARCB1-deficient sinonasal carcinoma. Diagnosis of SMARCB1-deficient sinonasal carcinoma should be considered in all undifferentiated sinonasal carcinomas. Immunohistochemistry or molecular studies are mandatory to confirm the diagnosis and exclude other morphologically similar entities.

Oncocytic mucoepidermoid carcinoma of the parotid gland: case report.

Mucoepidermoid carcinoma is the most common malignant tumour of salivary glands. Oncocytic variant is rare and could be mistaken for benign entities like oncocytoma and Warthin tumour on cytology. We present a case of a 67-year-old female presented with left parotid gland mass, which was diagnosed as a benign oncocytoma on cytologic examination. Later, the patient underwent left parotidectomy where the histologic examination revealed a malignant oncocytic mucoepidermoid carcinoma. The distinction between these entities is essential to get a proper management for the patient. On cytology alone, it is quite difficult to differentiate; however, histologic examination shows malignant features including infiltrative borders, lymphovascular invasion and perineural invasion excluding a benign tumour. The presence of mucin is an important clue to suspect oncocytic mucoepidermoid carcinoma. Ancillary studies can help reach a wright diagnose, as oncocytic mucoepidermoid carcinoma is positive for P63 and has MAML2 translocation.

Lobular Mammary Carcinoma Presenting as an Obstructing Rectal Mass.

Breast cancer is the leading cause of cancer death in women, and while metastasis is common to areas like the bone, lungs, and brain, it is rare to metastasize to the gastrointestinal tract and especially to the rectum. Due to the rarity of this condition and its resemblance clinically and radiologically to primary gastrointestinal tract tumors, diagnosis and treatment are challenging. We present a case of metastatic lobular mammary carcinoma in a 52-year-old Bahraini woman who presented with an obstructing rectal mass.

Lung Cancer in Bahrain: Histological and Molecular Features.

OBJECTIVES: To define the histological types of primary lung cancer in Bahrain and to determine prevalence of EGFR and ALK mutation in patients with non-small cell lung carcinoma. METHODS: Data regarding Bahraini patients diagnosed with primary lung cancer between January 2013 and December 2018 were collected from the lab information system in Salmaniya medical complex, Manama, Bahrain. RESULTS: One hundred and forty-three Bahraini patients were diagnosed with lung cancer in the study period. 67.1% of the patients were male. The mean age at diagnosis was 68 years. The most common histological type was adenocarcinoma (58%), followed by squamous cell carcinoma (19%). EGFR mutation was found in 21.5% of non-small cell lung cancer cases with predominance of exon 19 deletions (29%) and exon 21 nucleic acid changes (21%). ALK mutation was found in 10.5% of EGFR negative patients. CONCLUSION: Adenocarcinoma is the most common primary lung cancer in Bahrain. Genetic mutations of EGFR and ALK genes were found in 21.5% and 10.5% of adenocarcinoma cases, respectively.

IgG4-Related Disease, the Malignancy Mimicker: Case Series from Bahrain.

IgG4-related disease is an evolving immune-mediated condition. The hallmark of this condition is IgG4(+) plasma cells infiltration of the affected organs accompanied by a variable degree of fibrosis and occasionally elevated serum IgG4 level. It links many conditions that were once recognized as isolated unrelated idiopathic single organ disorders (e.g., autoimmune pancreatitis, Mikulicz syndrome, and retroperitoneal fibrosis) under one umbrella. It usually presents clinically as tumor-like swelling of the involved organs that can be misdiagnosed as neoplasia. In this case series, we present four cases that were considered as neoplasia but turned out to be IgG4-related disease, we demonstrate the protean manifestations of this condition and variable organs involvement, and we share our experience in using rituximab as the steroid sparing immunosuppressant agent to control this disease.

Spectrum of lymphoma in Bahrain. A retrospective analysis according to the World Health Organization classification.

OBJECTIVES: To determine the spectrum of various types of lymphoma in Bahrain according to the latest World Health Organization classification criteria.  Methods: A retrospective review was conducted for all new lymphoma cases diagnosed at Salmaniya Medical Complex, Manama, Bahrain during the period from January 2010 to December 2015.  Results: Two hundred and twenty-one new cases of lymphoma in Bahraini patients were diagnosed in the study period. Eighty patients had Hodgkin lymphoma, 140 had non-Hodgkin lymphoma, and one patient had composite lymphoma. In the Hodgkin lymphoma group, nodular sclerosis type was the most frequent type (48.75%), followed by mixed-cellularity type (27.5%), and nodular-lymphocyte predominant type (16.25%). In the non-Hodgkin lymphoma group, 124 (88.6%) cases were B-cell lymphomas, while the remaining were T-cell lymphomas. Diffuse large B-cell lymphoma was the most frequent type of non-Hodgkin B-cell type lymphoma (55.7%), followed by follicular lymphoma (10%).  Conclusion: The distribution of lymphoma in Bahrain is similar to neighboring Middle East countries with a predominance of Hodgkin lymphoma and diffuse large B-cell lymphoma.

Classification of thyroid fine-needle aspiration cytology into Bethesda categories: An institutional experience and review of the literature.

BACKGROUND: Fine-needle aspiration cytology (FNAC) of thyroid is the initial screening test for thyroid nodules. The Bethesda system classifies thyroid FNAC into six categories. Each category is linked to a malignancy risk and has a recommended clinical management. The aim of this study is to analyze the thyroid cytology smears by Bethesda system and to correlate the diagnosis of cytopathology with histopathology, whenever surgery was done. MATERIALS AND METHODS: This study presents our experience with the Bethesda system in 681 thyroid FNAs from 632 patients in the period between January 2013 and December 2016. RESULTS: Categories were as follows: 10.1% were Category I (nondiagnostic), 68.8% Category II (benign), 12.4% were Category III (atypia of undetermined significance), 2.9% were Category IV (suspicious for follicular neoplasm), 2.6% were Category V (suspicious for malignancy), and 4.1% were Category VI (malignant). Surgery was done on 126 nodules from 119 patients with an overall rate of malignancy of 27.8% (35/126 nodules). CONCLUSION: The Bethesda System for Reporting Thyroid Cytopathology proved to be an excellent reporting system.

Plasmacytoma as a Mimicker of Colonic Carcinoma in an Elderly Man.

Multiple myeloma is a neoplastic proliferation of monoclonal plasma cells. Although it is usually restricted to the bone marrow, extraskeletal spread in the form of localised extramedullary collections of malignant plasma cells (plasmacytomas) can occur. However, gastrointestinal tract involvement in multiple myeloma is rare and overt gastrointestinal bleeding from plasmacytoma is uncommon. We report a case of colonic plasmacytoma which presented with bleeding per rectum and was initially misdiagnosed as colonic neuroendocrine carcinoma. Later the patient presented with recurrence of the colonic mass along with multiple lytic bone lesions. The diagnosis of colonic plasmacytoma with progression into multiple myeloma was given. We also discuss here the diagnostic difficulty of plasma cell neoplasms in small biopsies of the colon.

Reasons for rarity of anal melanocytic naevi.

In the last 16 years only seven definite cases of anal melanocytic naevi have been reported in the literature. We describe three new cases, none of which were suspected clinically and were incidentally diagnosed on histological examination of haemorrhoidectomy specimens. The infrequency of these special site flexural melanocytic lesions may be related to changes in the involutionary mechanisms of the anal melanocyte proliferation. However, other factors related to the low detection rates by clinicians and pathologists need also to be considered.

Merkel Cell Carcinoma Arising in an Epidermal Cyst.

Merkel cell carcinoma is a rare aggressive primary cutaneous neuroendocrine tumor. It is associated mostly with malignant skin lesions. Rare cases in the literature described its association with benign skin adnexal lesions. We present here an additional case of Merkel cell carcinoma arising from an epidermal cyst located in the left arm of a 57-year-old male. The tumor was composed of lobules of monotonous round cells with dusty chromatin. It was positive for cytokeratin 20 and neuroendocrine markers. Patient was treated with surgical resection and radiation to the axilla. He is well and free of disease after 5 years of follow-up.