An arachnoid cyst is a rare cerebrospinal fluid–filled non-neoplastic cystic lesion. Most arachnoid cysts are asymptomatic; however, depending on their location and size, they may show various clinical symptoms and rarely can cause serious complications. We report a case of an arachnoid cyst incidentally found in a 25-year-old male soldier, which was not the cause of death. A 2.3×1.7 cm unilocular cystic lesion filled with colorless serous fluid was observed near the interpeduncular fossa of the brain. Microscopy revealed the cyst membrane to be lined by a single layer of meningothelial cells with no edema or inflammatory reaction in the surrounding structures. Considering the medical history, circumstances of death, and autopsy findings, the cause of death was determined to be sudden cardiac death, and the cyst found in the brain was consistent with an arachnoid cyst. Reviewing this case and related literature would help to determine the cause and manner of death if an arachnoid cyst is incidentally found during an autopsy.

Calcific aortic valve disease (CAVD) is an uncommon disease in young adults, unless there is a congenital anomaly in the aortic valve. We report a case of CAVD identified during the autopsy of a 26-year-old male soldier who died in his room while sitting on a chair. Macroscopic examination revealed multiple nodules in the semilunar cusps of the aortic valve, and that the commissure of semilunar valve cusps was slightly fused. Under microscopic examination, fibrotic nodules with neovascularization were identified in the fibrosa layer of the aortic valve, although neither calcification nor chronic inflammation were identified in the fibrotic nodule. Mitral valve prolapse and left ventricular hypertrophy with interstitial fibrosis were also identified. Microscopic examination of CAVD typically shows calcified nodules in the fibrosa layer of the valve, but fibrosis alone, without calcification, can be observed in the early stage of the disease. Death from CAVD is rare in young adults, so careful examination must be taken not to misdiagnose this condition with rheumatic valvular disease, which is relatively common in this population.

Although most cerebral aneurysms are considered as acquired degenerative lesions, diverse anatomical variations in the circle of Willis have been encountered, some of which may play an important role in lesion hemodynamics and pathogenesis. The coalescence of the small vascular plexus to form the anterior communicating artery at the 6-7-week embryological stage may lead to developmental variations, such as fenestration and duplication. Herein, we report a rare anatomical variant of the anterior communicating artery that was concomitantly identified with a ruptured aneurysm. Both the right and left anterior cerebral arteries were connected by three anterior communicating arteries. A vertical segmental artery was present and connected the two anterior communicating arteries, forming an H-shape or plexiform structure. Furthermore, a 0.6×0.4 cm-sized saccular aneurysm with antero-inferior projection was present in the middle anterior communicating artery. The combination of triplication and H-shape in the present case was compared to previously reported anatomical variants.

We present an autopsy case of a 19-year-old man with a history of epilepsy whose unwitnessed sudden death occurred unexpectedly in the night. About 4 years before death, he was diagnosed with unilateral optic neuritis (ON). Demyelinating disease was suspected, but he was lost to follow up after the recovery. Six months before death, he received a second dose of mRNA coronavirus disease 2019 (COVID-19) vaccine. Three months before death, he experienced epileptic seizures for the first time. Seventeen days before death, he was infected with COVID-19, which showed self-limited course under home isolation. Several days before death, he complained of seizures again at night. Autopsy revealed multifocal gray-tan discoloration in the cerebrum. Histologically, the lesions consisted of active and inactive demyelinated plaques in the perivenous area of the white matter. Perivascular lymphocytic infiltration and microglial cell proliferation were observed in both white matter and cortex. The other major organs including heart and lung were unremarkable. Based on the antemortem history and postmortem findings, the cause of death was determined to be multiple sclerosis with suspected exacerbation. The direct or indirect involvement of cortex and deep gray matter by exacerbated multiple sclerosis may explain the occurrence of seizures. Considering the absence of other structural abnormalities except the inflammatory demyelination of the cerebrum, fatal arrhythmia or laryngospasm in the terminal epileptic seizure may explain his sudden unexpected death in the benign circumstances. In this case, the onset of seizure was preceded by COVID-19 vaccination, and the exacerbation of seizure was preceded by COVID-19 infection, respectively. Literature reporting first manifestation or relapse of multiple sclerosis temporally associated with COVID-19 vaccination or infection are reviewed.

In majority of deaths from asphyxiation that affect the cerebral blood flow, compression occurs at the neck. Compressive asphyxia caused by a heavy weight is usually the result of an accident. The authors used the Korean national police agency's scientific crime analysis system to identify two cases of suicide by strangulation which were not otherwise specified, wherein asphyxiation occurred from an object pressing on the neck. In the first case, a man in his 50s died after the compression of his neck with a barbell shaft using a bench press. In the second case, a man in his 80s died due to compression from the side bar of a single bed that pressed on his neck. As far as the authors know, there have been no reported cases of suicide in forensic literature that occurred due to compression from an object such as a barbell shaft of a bench press or a side bar of a bed. Upon classifying the types of asphyxiation, accurate statistics should be prepared and researched, with accurate understanding and classification of the terms therein. Each case in the present report is discussed along with a brief literature review.

Dry ice is a solid form of carbon dioxide and is commonly used in everyday life to keep food or medicine cold. In South Korea, there have been rare cases of carbon dioxide asphyxiation and poisoning from dry ice, though there have been no reports of its use in suicide. In the first case, a man was found lying down dead and left a large amount of dry ice in his room. In the second case, a man died by tying a belt around his neck after placing a plastic bag filled with dry ice over his head. The third death was by placing a large amount of dry ice in a large rubber basin in his room and filling it with water. Dry ice itself is mostly harmless, but if it is not handled carefully in a confined space, it can cause accidents due to accidental oxygen deprivation. Its easy availability in everyday life also means it is likely to be misused for suicidal purposes. Investigators should consider the potential for asphyxiation or poisoning incidents if they discover dry ice or its packaging at the forensic scene.

Hanging is the most common form of suicide, but the use of a single ligature in a suicide pact is very rare. The authors identified three cases of double hanging through the National Police Agency's Scientific Crime Analysis System over 11 years in Korea, from 2008 to 2018. Of the six deaths, all but one were suicides; one was a victim of murder (suicide after murder). A couple was found hanging by a single ligature over a beam, wherein a man hanged himself using the weight of the woman he had strangled to death. A mother and her daughter used a chest of drawers as a fulcrum off which they hanged themselves, with one on each side of the drawers, using a single rope. Two lovers were found sitting at each end of the rope, using a single ligature, with a tree branch as an abutment. Each of these cases is discussed and reported along with a brief literature review. In a double hanging case, investigators should be cautious in determining the manner of death by distinguishing between a suicide pact from a homicide-suicide.

Shallow water blackout (SWB) is defined as loss of consciousness due to hypoxia during underwater swimming or breath-holding, usually in shallow waters. To date, no cases of SWB-induced drowning have been reported in the Republic of Korea. Here, we report two cases of SWB, followed by drowning, with autopsy findings. Two men, aged 20 (case 1) and 25 (case 2) years, suddenly lost their consciousness during underwater swimming and escape training, respectively. Postmortem examination revealed foamy fluid within trachea and bronchus, pulmonary edema, and sphenoid sinus fluid, which are commonly observed findings in drowning cases. None of the organs in either case showed pathologic alterations, except for hypoplastic coronary artery disease incidentally found in case 2. Pathologists should be aware of this distinct pathologic entity to avoid misdiagnosing the cause or manner of death.

We present autopsy findings of a 22-year-old man who developed chest pain 5 days after the first dose of the BNT162b2 mRNA vaccine and died 7 hours later. Histological examination of the heart revealed isolated atrial myocarditis, with neutrophil and histiocyte predominance.Immunohistochemical C4d staining revealed scattered single-cell necrosis of myocytes which was not accompanied by inflammatory infiltrates. Extensive contraction band necrosis was observed in the atria and ventricles. There was no evidence of microthrombosis or infection in the heart and other organs. The primary cause of death was determined to be myocarditis, causally-associated with the BNT162b2 vaccine.

We present a rare case of spindle cell oncocytoma (SCO) of the sella turcica with malignant histologic features and rapid progression. A 42-year-old woman experienced bilateral blurred vision and was preoperatively misdiagnosed as having a pituitary macroadenoma on magnetic resonance imaging. After surgery, SCO was diagnosed by the histopathologic features of interlacing fascicles of spindle tumor cells with finely granular, eosinophilic cytoplasm. Focal anaplastic changes and necrosis were present. Immunohistochemically, the tumor cells were positive for vimentin, epithelial membrane antigen, S-100, galectin-3, and thyroid transcription factor 1. Four months later, the tumor had progressed, and second surgery with adjuvant radiotherapy was performed; the patients remains under observation. In this report, we proposed distinctive radiologic features for differential diagnosis between SCO and other pituitary tumors.