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Primary gastric yolk tumours are extremely rare. We report a 52-year-old male who presented to the Sultan Qaboos University Hospital, Muscat, Oman, in 2017 after having undergone a gastrectomy abroad due to a suspected poorly-differentiated adenocarcinoma. The patient subsequently returned to Oman to receive chemotherapy. However, while undergoing chemotherapy, an abdominal computed tomography scan revealed a lobulated mesenteric mass. Microscopic examination of the resected lesion confirmed a diagnosis of a yolk sac tumour. The mass was diffusely positive for α-fetoprotein (AFP) and a gastric carcinoma stain was negative. Gastrectomy slides from the patient’s previous surgery were examined retrospectively. The morphology was typical for a yolk sac tumour and was negative for epithelial markers. An AFP stain showed diffuse immunoreactivity. Thus, the patient was deemed to have had a primary gastric yolk sac tumour which had later metastasised to the mesocolon. Germ cell tumour protocols were initiated and the patient responded well to treatment. Keywords: Yolk Sac Tumor; Germ Cell Tumor; Gastrectomy; Metastasis; Diagnostic Errors; Case Report; Oman.

Rosai-Dorfman disease (RDD) is a rare benign proliferative histiocytic disorder characterised by massive lymphadenopathy. While extranodal involvement can occur in generalised RDD, isolated soft tissue RDD (STRDD) is extremely rare. We report a 17-year-old male patient who presented to the maxillofacial outpatient department of the Sultan Qaboos Hospital, Salalah, Oman, in 2015 with a painless cheek mass which had been slowly growing over the previous two months. Routine histopathological examinations and immunohistochemistry confirmed a diagnosis of STRDD. Currently, surgical excision is considered to be the most effective curative treatment for STRDD, as the outcomes of other treatment modalities are still unknown. Despite its rarity, STRDD should be considered in the differential diagnosis of histiocytic soft tissue lesions.

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm with a non-specific and insidious presentation further complicated by the difficult diagnostic and therapeutic assessment. It has a low to intermediate risk of recurrence and metastasis. Unlike other soft tissue sarcomas or histiocytic and dendritic cell neoplasms, cytogenetic studies are very limited in FDCS cases. Although no specific chromosomal marker has yet been established, complex aberrations and different ploidy types have been documented. We report the case of a 39-yearold woman with FDCS who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in February 2013. Ultrastructural, immunophenotypical and histological findings are reported. In addition, karyotypic findings showed deletions of the chromosomes 1p, 3q, 6q, 7q, 8q and 11q. To the best of the authors’ knowledge, these have not been reported previously in this tumour. Techniques such as spectral karyotyping may help to better characterise chromosomal abnormalities in this type of tumour.

Objectives: Mutations/deletions affecting the TP53 gene are considered an independent marker predicting a poor prognosis for patients with diffuse large B-cell lymphoma (DLBCL). A cohort within a genetically isolated population was investigated for p53 mutation/deletion status. Methods:Deoxyribonucleic acid (DNA) samples were extracted from 23 paraffin-embedded blocks obtained from DLBCL patients, and subjected to polymerase chain reaction (PCR) amplification and sequencing of exons 4–9 of the p53 gene. Results: While 35% of patients analysed displayed allelic deletions (P

Plasma cell myeloma is an uncommon disease which, besides primarily involving the bone marrow, has a tendency to involve other organs thus presenting with different clinical manifestations. While pleural effusions are infrequent in this disease, true myelomatous pleural effusions are extremely rare. We report the case of a middle-aged Omani man with relapsed plasma cell myeloma who developed bilateral pleural effusions. The diagnosis of myelomatous pleural effusion was made by finding many abnormal plasma cells as well as a high level of a monoclonal protein (IgG κ) in the pleural fluid. In spite of a good initial response to therapy, the patient had progressive disease and died 6 months later with bacterial sepsis. We present a review of the literature that indicates the rarity of such a manifestation and its association with poor prognosis and short survival.

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm with a non-specific and insidious presentation further complicated by the difficult diagnostic and therapeutic assessment. It has a low to intermediate risk of recurrence and metastasis. Unlike other soft tissue sarcomas or histiocytic and dendritic cell neoplasms, cytogenetic studies are very limited in FDCS cases. Although no specific chromosomal marker has yet been established, complex aberrations and different ploidy types have been documented. We report the case of a 39-yearold woman with FDCS who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in February 2013. Ultrastructural, immunophenotypical and histological findings are reported. In addition, karyotypic findings showed deletions of the chromosomes 1p, 3q, 6q, 7q, 8q and 11q. To the best of the authors’ knowledge, these have not been reported previously in this tumour. Techniques such as spectral karyotyping may help to better characterise chromosomal abnormalities in this type of tumour.