ABSTRACT Virchow’s law of thrombosis states that thrombosis in a vessel occurs as a combination of the following: (i) injury to the vessel wall, (ii) stasis of blood flow, and (iii) blood hypercoagulability. Injury to the wall includes infection/inflammation and/or injury to the resident cells of the wall. We postulate that in COVID-19, the SARS-CoV-2 virus directly infects the alveolar type II cell or directly or indirectly infects/injures the pericyte, promoting inflammation and interaction with endothelial cells, thereby causing a cascade of events leading to our observation that thrombosis occurred within the walls of the pulmonary vessels and not in the lumen of the vascular circulation.

ABSTRACT Dermatomyositis is a heterogeneous systemic disease, with 7% to 10% of the individuals presenting the Anti MDA-5 antibody. This subset of patients has clinically amyotropic dermatomyositis, presenting with cutaneous ulcer and rapidly progressive interstitial lung disease. We report the case of a 22-year-old male with a six-month history of low-grade fever associated with myalgia, polyarthralgia, and marked weight loss. He had a history of shortness of breath and high-grade fever 15 days before admission. His clinical features and imaging workup were consistent with acute respiratory distress syndrome. A nasal swab was positive for H1N1 influenza virus infection. During the disease investigation, he succumbed after nine days of admission. The autopsy examination showed diffuse alveolar damage on a background of non-specific interstitial pattern of injury in the lungs. His postmortem muscle biopsy revealed subtle changes of inflammatory myopathy. The brain showed diffuse subarachnoid hemorrhage. Evaluation of postmortem serum sample revealed positivity for Anti MDA-5 and Ro-52 antibodies. This was a case of Anti MDA-5 and Ro-52 associated dermatomyositis with non-specific interstitial pneumonia pattern of lung injury complicated with H1N1 influenza pneumonia, leading to diffuse alveolar damage and subsequent respiratory failure and death. Serum Anti MDA-5 antibodies represent an important biomarker for diagnosing and predicting prognosis for patients with idiopathic inflammatory myopathies, especially clinically amyopathic dermatomyositis. Anti-Ro-52 has been reported in a wide variety of autoimmune diseases, particularly in myositis, scleroderma, and autoimmune liver diseases. Ro-52 autoantibodies are associated with interstitial lung disease (ILD), and their presence should encourage the clinician's curiosity to search for ILD.

ABSTRACT Cryptococcosis occurs primarily in immunocompromised patients. It is difficult to suspect in an immunocompetent patient presenting with a headache. The clinical manifestations of cryptococcosis can be subtle in a patient whose immune system is responding, but inadequate. This is the report of a case of fatal cryptococcosis initially misdiagnosed as a sinus headache on the basis of a telephone call, and then misdiagnosed as aseptic meningitis on the basis of mild findings and negative cerebrospinal fluid cultures. Autopsy revealed unsuspected severe cryptococcal meningoencephalitis. Cerebrospinal fluid nuclear acid amplification (NAA) panels including Cryptococcus should enable the diagnosis of unsuspected cryptococcal meningitis in most cases, but can be false positive, which could be adjudicated by cryptococcal antigen and culture. It will remain important to test for cryptococcal antigen and to maintain a broad differential diagnosis for all patients with meningitis.

ABSTRACT Castleman disease (CD) is a rare, benign lymphoproliferative disorder, mostly involving the mediastinal lymph nodes, but can occur wherever lymphoid tissue is found. With only a few published case reports, there needs to be more literature on its cytological findings. We report the case of a 63-year-old female presenting with left upper cervical swelling. Fine needle aspiration cytology smears showed variably sized lymphoid follicles with diminished germinal centers, prominence of follicular dendritic cells, and capillaries traversing some of the follicles. The possibility of a hyaline-vascular type of Castleman disease was suggested. Histopathology confirmed the cytological diagnosis. The index case is being presented to discuss the cytological features of the CD along with its histological and immunohistochemical correlation.

ABSTRACT Melanoma arising in the hard palate is an exceedingly rare entity, comprising a minute fraction of all melanoma cases. The absence of specific clinical signs often leads to delayed diagnosis and subsequent challenges in treatment planning. We discussed the existing literature to elucidate the epidemiology, risk factors, and molecular pathways associated with melanoma of the hard palate. Additionally, we discuss the importance of a multidisciplinary approach involving dermatologists, otolaryngologists, oncologists, and pathologists in diagnosing and managing this condition. A 62-year-old male patient presented with a pigmented lesion on the hard palate mucosa, which was initially asymptomatic but gradually increased in size. Biopsy revealed melanoma, confirmed through immunohistochemical staining. Staging investigations indicated a metastatic disease. Surgery followed by adjuvant therapy was planned; however, he was lost for the follow-up. Melanoma originating from the hard palate mucosa is exceedingly rare, posing diagnostic and therapeutic challenges. Early detection, accurate diagnosis, and prompt multidisciplinary management are crucial for optimal outcomes. This case underscores the importance of comprehensive evaluation and tailored treatment strategies in patients with uncommon mucosal melanomas.

ABSTRACT Dentinogenic ghost cell tumor (DGCT) is a rare benign neoplasm form of calcifying odontogenic cyst (COC) characterized by ghost cells. Although benign, it presents an aggressive behavior. DGCT accounts for 2% to 14% of all COCs and less than 0.5% of all odontogenic tumors. It is a benign odontogenic tumor despite its local invasion and the likelihood of recurrence. To detect recurrence, central DGCT patients must be monitored long-term. We present the case of a 51-year-old male who reported pain in the right upper back tooth region. On examination, a soft to firm, bright red swelling was present in the buccal vestibule and gingival margin of the maxillary right first and second molar, which extended up to the palate. Histopathological analysis confirmed the diagnosis of a DGCT, which occurred in a previously treated calcifying odontogenic cyst. The case is reported here, along with a review of the literature update of such recurred instances in the past.

Abstract Primary cardiac tumors are rare. The cardiac sarcomas are the most common malignant cardiac tumors. These tumors have a dismal prognosis with an overall median survival of 25 months. Clinical features include dyspnea, arrhythmias, pericardial effusions, heart failure, and sudden cardiac death. The diagnosis is often challenging. Therefore, the cardiac imaging workup plays a central role in addition to a high clinical suspicion in the setting of atypical presentations that do not respond to standard therapies. The echocardiography, computed tomography, and cardiac MRI are crucial in clinching the diagnosis. Multimodal treatment with surgery, chemotherapy, and radiotherapy has been shown to improve outcomes, as opposed to using either of these modalities alone. We describe the case of a 30-year-old gentleman with COVID-19 infection who developed recurrent hemorrhagic pericardial effusions refractory to standard treatment and was eventually diagnosed as a case of pericardial angiosarcoma after his biopsy revealed the diagnosis and staging was performed using PET–CT–FDG scan. Our case re-emphasizes the importance of considering a malignant etiology early in the course of the disease presentation, especially in recurrent hemorrhagic effusions despite an inflammatory cytologic diagnosis of fluid. It also highlights the place for cardiac CT and MRI to ascertain the location and spread and to plan the further course of treatment. If diagnosed early, the estimated survival time can be prolonged by instituting a multimodal approach.

ABSTRACT The vasa vasorum of the large pulmonary vessels is involved in the pathology of COVID-19. This specialized microvasculature plays a major role in the biology and pathology of the pulmonary vessel walls. We have evidence that thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels during severe COVID-19 causes ischemia and subsequent death of the pulmonary vasculature endothelium. Subsequent release of thrombi from the vasa interna into the pulmonary circulation and pulmonary embolism generated at the ischemic pulmonary vascular endothelium site, are the central pathophysiological mechanisms in COVID-19 responsible for pulmonary thromboembolism. The thrombosis of the vasa vasorum of the large and medium-sized pulmonary vessels is an internal event leading to pulmonary thromboembolism in COVID-19.

ABSTRACT The lymphocyte-depleted classic Hodgkin lymphoma (LDCHL), the rarest subtype of classic Hodgkin lymphoma (CHL), is usually diagnosed at an advanced stage (stage IV) and one that unusually involves the liver, causing a rapidly progressive clinical course. We describe a 40-year-old immunocompromised man presenting with a progressive non-cholestatic jaundice and intermittent fever. The abdominal ultrasonography revealed a nodular liver with coarse echotexture and periportal hypodensities. The thoracic and abdominal contrast-enhanced computed tomography revealed right cervical and paraaortic lymphadenopathy, hepatosplenomegaly, diffuse mural thickening of duodenal and jejunal loops, and bilateral lobulated kidneys. Subsequently, he succumbed to his illness secondary to refractory septic shock. On postmortem examination, he was diagnosed with classic Hodgkin lymphoma (lymphocyte-depleted type) involving paraaortic and mediastinal lymph nodes based on morphology and immunochemistry findings. The lymphomatous process involved the liver (causing multiacinar confluent hepatic necrosis) and spleen, both showing tuberculous foci. This autopsy case depicts an uncommon case of acute liver failure due to infiltration of the liver by LDCHL in an HIV-infected patient. The findings of angiotropism and angioinvasion establish the pathological mechanism of liver failure (hepatocellular necrosis) in such cases.

ABSTRACT The effectiveness of the autopsy as an educational tool in forensic medicine courses has been widely acknowledged, and medical students were expected to attend regularly. Nevertheless, the use of autopsies for teaching has dramatically declined in recent years and worldwide despite their high-value benefits. This study aims to understand the importance and relevance of attending autopsies during forensic teaching sessions and identify any challenges that may impede attendance. A self-administered online questionnaire that assesses the knowledge, attitudes, and practices related to autopsies attendance was distributed to fourth-year medical students at the National Defence University of Malaysia and Universiti Sains Islam Malaysia. A total of 99 respondents were involved in this study. Our findings indicate that most respondents (over 85%) demonstrated good knowledge of forensic medicine. Pearson's statistical test revealed a significant correlation between the knowledge and students' attitudes toward autopsy. This study demonstrates the need to strategically integrate autopsy attendance into medical curricula to encourage constructive attitudes and practices among medical students. Students gain the most benefits from frequently attending autopsies. Passionate educators can conduct preparatory sessions to set expectations and address concerns, encourage students to process their experiences, and reinforce learning outcomes in the mortuary setting. Mandatory autopsy teaching should be integrated into the curriculum to ensure medical students have the necessary skills and knowledge to become competent doctors.

ABSTRACT Atypical parathyroid tumor (APT) is a rare neoplasm of the parathyroid gland, which shows atypical cytological or architectural features and lacks definite diagnosis criteria for malignancy. These cases can cause diagnostic challenges owing to their rarity and similarity with thyroid neoplasm on imaging and fine needle aspiration cytology. Also, differentiating APT from giant parathyroid adenoma or parathyroid carcinoma can be challenging based on clinical, imaging or cytological features. A 49-year-old male presented with clinical features of hyperparathyroidism. On laboratory evaluation, his serum calcium and serum parathyroid hormone was elevated. Imaging studies suggested a possibility of left inferior parathyroid neoplasm, and fine needle aspiration cytology showed features suggestive of parathyroid neoplasm. However, exact categorization of parathyroid tumor was difficult in pre-operative work-up. Possibilities of giant parathyroid adenoma as well as parathyroid carcinoma were considered. A final diagnosis of an atypical parathyroid tumor was made after detailed histopathological evaluation given focal capsular invasion but lack of unequivocal evidence of malignancy in the resected specimen. APT is a rare neoplasm of uncertain malignant potential. Knowledge of the radiological and pathological features will be helpful in accurately identifying the lesion and avoiding misdiagnosis.