Life-threatening gastrointestinal haemorrhage requiring surgical resection caused by SARS-CoV-2 induced ANCA associated vasculitis: A case report.

Introduction and importance: SARS-CoV-2 infection has been linked to the de novo diagnosis of various autoimmune conditions as well as flares in pre-existing disease. With such high prevalence of SARS-CoV-2 in the community, it is important to consider rare manifestations of autoimmune conditions when patients present with severe symptoms. Multi-specialty care is required to ensure optimal outcomes and prompt diagnosis. Case presentation: A 28-year-old male presented to our tertiary referral centre with progressive debilitating polyarthritis, a purpuric rash on both flanks and aphthous ulcers 6 weeks after infection with SARS-CoV-2. On the second day of admission, he developed severe gastrointestinal haemorrhage requiring multiple blood transfusions. Attempted angioembolisation failed to identify a site of active haemorrhage. On failing trial of conservative management, the decision was made to perform an exploratory laparotomy. The small bowel was found to have an extensive vasculitis requiring resection to control haemorrhage. Autoimmune serology revealed c-ANCA positivity with anti-PR3 antibodies. Clinical discussion: Patients presenting with acute vasculitic pathologies related to SARS-CoV-2 have the potential to rapidly progress to severe life-threatening gastrointestinal haemorrhage. Prompt surgical management is appropriate in selected cases. Conclusion: In the current era of COVID-19, the differential diagnosis of SARS-CoV-2 induced ANCA vasculitis must be considered for such cases with gastrointestinal haemorrhage. Compilation of similar cases and further studies are required to determine an optimal management pathway for these patients.

Penile Epithelioid Angiomatoid Nodule.

Cutaneous epithelioid angiomatoid nodule is a rare clinical entity that is common on the trunk and limbs. This is the first report of penile cutaneous epithelioid angiomatoid nodule. Although it is a benign entity, it must be differentiated from vascular neoplasms, as it can bear similar clinical and pathologic features.

Detection of MYC rearrangement in high grade B cell lymphomas: correlation of MYC immunohistochemistry and FISH analysis.

The aim of this study was to analyse sensitivity, specificity and predictive values of recently available MYC immunohistochemistry (IHC) against the currently standard diagnostic method, fluorescence in situ hybridisation (FISH) analysis. MYC IHC and FISH analyses were performed on 30 cases of diffuse large B cell lymphoma (DLBCL) with 80% or more Ki-67 index, one case of DLBCL transformed from follicular lymphoma, three cases of B cell lymphoma intermediate between DLBCL and Burkitt lymphoma (IM), six cases of Burkitt lymphoma (BL) and one case of reactive lymph node. The inclusion criteria of high Ki-67 index, more than 80%, was imposed to exclude dependence of MYC positivity on Ki-67 positivity. The indices of specificity and positive predictive value (PPV) were low and varied widely with different thresholds of IHC positivity in percentage. At the threshold of 40% IHC positivity, specificity index was 0.45 and PPV was 0.37. At the threshold of 50% and 70% IHC positivity, specificity indices were 0.61 and 0.84, and PPVs were 0.45 and 0.67, respectively. Good sensitivity and negative predictive value (NPV) were maintained at all different thresholds. A heterogenous staining pattern of IHC was also noted. The heterogeneous IHC staining pattern observed warranted caution in interpretation and counting of IHC positive cells. MYC protein expression detected by IHC was more common than MYC translocation detected by FISH analysis. As a result, low specificity and PPV of MYC IHC, in relation to FISH analysis, were observed despite good sensitivity and NPV.

B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma and classical hodgkin lymphoma: diagnosis by fine-needle aspiration cytology.

A 58-year-old lady presented with mediastinal lymphadenopathy. A thoracoscopic ultrasound-guided fine-needle aspiration showed large atypical epithelioid cells arranged in cohesive sheets and dispersed as single cells with intact cytoplasm amid a background of lymphocytes and histiocytes. A cytological diagnosis of "a malignant neoplasm" was made, raising a broad list of differential diagnoses. A broad panel of immunocytochemical stains performed on the cell block was indicative of a lymphoproliferative disorder, but the immunophenotype was intermediate between diffuse large B cell lymphoma (DLBCL) and classical Hodgkin lymphoma (cHL). Diffuse and strong reactivity to CD20, CD79a, and PAX-5, and weak reactivity to CD30, was in favor of a DLBCL, or more precisely mediastinal (thymic) large B cell lymphoma (MLBL). However, there were negative staining for LCA, OCT-2, and BOB-1 as well as positive staining for EBV-encoded RNA, which were against a diagnosis of MLBL and raised the possibility of cHL. The absence of RS cells and the typical mileu, the negativity for CD15 and the strong positivity of CD20 and PAX-5 were against a diagnosis of cHL. On this basis, the diagnosis of "B-cell lymphoproliferative disorder with features intermediate between DLBCL and cHL" was rendered. The diagnosis was subsequently confirmed on excisional biopsy. This case report demonstrates broad differential diagnoses raised by this diagnostic entity and the importance of an adequate cell block for accurate designation.