Hemosiderotic/aneurysmal variant of dermatofibroma (DF) is infrequent and may be misdiagnosed with malignant lesions. We report the case of a giant (7.6cm) subcutaneous hemosiderotic/aneurysmal DF (H/ADF) of the thigh in a 53-year-old female patient. Internal arterial and venous hypervascularity was seen by spectral Doppler ultrasound. Magnetic resonance image showed a discrete homogeneous hypointense in T1-weighted images (WI) and T2-WI mass, with hyperintense areas in fat-suppressed T2-WI. The histology revealed a monotonous fusocelular proliferation without atypia, positive for CD163, factor XIIIa and CD10. Widely distributed hemosiderin pigment and two blood-filled pseudovascular spaces lacking endothelial lining were present. H/ADF was diagnosed. The mass was removed but surgical margins were affected. The patient did not present local relapse or distant metastasis. H/ADF are unusual cutaneous soft tissue tumours that can be clinically, radiologically and histopathologically confused with malignant lesions such as melanomas, vascular lesions or sarcomas, especially in giant cases.

BACKGROUND: Superficial siderosis (SS) of the central nervous system is a rare disease characterized by deposition of hemosiderin along the leptomeninges due to chronic or recurrent bleeding into the subarachnoid space. The association of unruptured intracranial aneurysm (IA) and cortical SS is quite rare.
METHODS: A systematic literature review to assess possible commonalities and/or differences of previous reported cases was undertaken. We report an additional case from our institution.
RESULTS: A 40-year-old woman presented with a history of generalized seizures over the past year. There was no clinical history suggestive of aneurysm rupture. Magnetic resonance imaging revealed 2 aneurysms of the right middle cerebral artery (MCA) bifurcation associated with hemosiderin deposition along the right sylvian fissure and a third aneurysm of the left MCA bifurcation. Magnetic resonance imaging showed wall enhancing thickening of the larger right MCA aneurysm. The patient underwent surgical clipping of all 3 MCA aneurysms in a staged procedure. Histological examination revealed hemosiderin deposits within the aneurysm wall and surrounding gliosis.
CONCLUSIONS: Our literature review found 24 reported cases of unruptured IA associated with cortical SS. The possible source for leakages could be neovessels visible in IA walls. The case reported illustrates an uncommon presentation of recurrent bleeding from an IA as a source of SS. The presence of an apparently unruptured IA surrounded by cortical SS on imaging studies is of high relevance as this should be considered a sign of aneurysm wall instability and should indicate prompt treatment.

Superficial siderosis (SS) is a rare condition in which chronic accumulation of the blood in the subarachnoid space over time leads to the buildup of hemosiderin deposits, which in turn cause neurological dysfunction in those affected. While reversibility of the damage done by this condition is nearly impossible, early detection can allow for immediate surgical intervention and thus prevent further progression of ataxia, hearing loss, and other neurological deficits caused by SS. We present a case of a 53-year-old male who was successfully diagnosed with SS secondary to a chronic post-traumatic pseudomeningocele and underwent surgical repair with the resolution of his symptoms. We aim to encourage more extensive workups for common neurological dysfunctions such as tinnitus or vertigo in patients who have a history of traumatic brain injury or any significant motor vehicle accidents.

Superficial siderosis is a disease in which hemosiderin is deposited under the leptomeninges and subpial layers of hindbrain structures, e.g., the cerebellum, brainstem, and eighth cranial nerve. The main symptoms of superficial siderosis are cerebellar ataxia, hearing loss, cognitive decline, and myelopathy. The activities of daily living of patients with superficial siderosis are severely impaired due to the progressive symptoms. Here, we report a patient with superficial siderosis whose symptoms deteriorated after lumbar subarachnoid-peritoneal (L-P) shunt surgery. She received L-P shunt surgery based on the diagnosis of idiopathic normal pressure hydrocephalus at another hospital. The patient had a history of cervical surgery, and a dural defect was identified at the C4-5 level by a detailed magnetic resonance imaging study. We hypothesized that the L-P shunt reduced cerebrospinal pressure and increased bleeding from the fragile vessels in the dural defect, which might have increased hemosiderin deposition.

We report a case of refractory acute myeloid leukemia with DEK-NUP214 rearrangement showing circulating monocytic blasts with abundant green cytoplasmic granules on the Wright-Giemsa stain. The granules were strongly positive for Perls\' Prussian blue, consistent with hemosiderin deposits. This previously unreported finding is suggestive of siderophage activity by leukemic blasts, likely associated with monocytic differentiation.

OBJECTIVE: Our recent studies have indicated that trace copper co-existed with iron in hemosiderin particles of human genetic iron overload. To understand this phenomenon, we analyzed hemosiderin particles in iron-overloaded rat liver by using scanning transmission electron microscopy - energy-dispersive X-ray (STEM-EDX) spectroscopy.
METHODS: Samples for STEM-EDX spectroscopy were prepared from the liver of rats administered an intraperitoneal injection of dextran iron.
RESULTS: The micro-domain analysis with STEM-EDX spectroscopy showed that dense bodies contained high levels of iron and trace copper. Quantitative analysis of copper levels in the liver specimen using atomic spectrophotometry showed that copper concentration in the liver was not increased by iron overload. These findings suggest that the overload of iron induced distribution of trace copper to hemosiderin particles without changing cellular copper levels.
CONCLUSIONS: Co-existence of copper with iron was observed in hemosiderin particles of the liver of an experimental model of iron overload, suggesting that iron overload induced distribution of trace copper into hemosiderin particles.

UNASSIGNED: In chronic venous insufficiency (CVI), an increase in venous pressure causes the passage of intravascular blood cells and molecules into the surrounding tissues and induces histopathological changes in the lower extremities, leading to increased pigmentation in the legs, ulceration, and tissue loss to various degrees. This study aimed to investigate whether an increase in venous pressure in the coronary veins can lead to the aforementioned histopathological changes.
UNASSIGNED: Twenty-four New Zealand rabbits were divided into the following three groups: experimental model of coronary venous hypertension (CVH) (n = 8), sham group (n = 8), and control group (n = 8). After 21 days postoperatively, tissue samples from each group were compared for perivascular inflammation, erythrocyte extravasation, macrophage infiltration, and hemosiderin deposits by histopathological scoring under a light microscope. Matrix metalloproteinase-2 (MMP-2) activation was evaluated using immunohistochemical staining.
UNASSIGNED: In the CVH group, hemosiderin accumulation was significantly higher than in the sham and control groups (1.0 (1.0-3.0), 0.0 (0.0-1.0), 0.0 (0.0-0.0); p < 0.001). Immunohistochemically, in the CVH group, MMP-2 levels were significantly higher than in the sham and control groups (2.0 (1.0-3.0), 0.0 (0.0-1.0), 0.0 (0.0-0.0); p < 0.001).
UNASSIGNED: This experimental study showed for the first time the histopathological and immunohistochemical changes in myocardial tissue, similar to those observed in CVI, as a result of increased coronary venous pressure due to coronary vein ligation. Further studies are needed to understand the clinical implications of these results.

BACKGROUND: The prevalence of renal masses has escalated as a result of the augmented utilization of cross-sectional imaging techniques. The approach to managing renal masses may exhibit variability contingent upon the subtype of renal cell carcinoma (RCC).
OBJECTIVE: This research aimed to distinguish between clear cell and papillary RCCs, utilizing dynamic contrast magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI).
METHODS: The study assessed the MR images of 112 patients with RCC. Two radiologists independently analyzed tumor size, vascular involvement, signal characteristics in T1- and T2-weighted sequences, the presence of hemosiderin, both microscopic and macroscopic fat content, enhancement patterns, and apparent diffusion coefficient (ADC) values derived from b-values of 1000 s/mm².
RESULTS: Seventy patients had clear cell RCC, and 42 had papillary. In the clear cell RCC, microscopic fat content was significantly higher than the papillary RCC (P < 0.001). However, in papillary RCC, hemosiderin content was substantially greater (P = 0.001). On T2-weighted MR images, clear cell RCCs were usually hyperintense, while papillary RCCs were hypointense (P < 0.001). Even though the rapid enhancement pattern was observed in clear cell RCCs, the progressive enhancement pattern was more prevalent in papillary RCCs (P < 0.001).
CONCLUSIONS: Hyperintensity on T2-weighted images, microscopic fat content, and rapid enhancement pattern may be indicative of clear cell RCC, whereas hypointensity on T2-weighted images, hemosiderin content, and a progressive contrast pattern may be diagnostic for papillary RCC.

BACKGROUND: The establishment of minimum standards for display selection for the whole slide image (WSI) interpretation has not been fully defined. Recently, pathologists have increasingly preferred using remote displays for clinical diagnostics. Our study aims to assess and compare the performance of three fixed work displays and one remote personal display in accurately identifying ten selected pathologic features integrated into WSIs.
METHODS: Hematoxylin and eosin-stained glass slides were digitized using Philips scanners. Seven practicing pathologists and three residents reviewed ninety WSIs to identify ten pathologic features using the LG, Dell, and Samsung and an optional consumer-grade display. Ten pathologic features included eosinophils, neutrophils, plasma cells, granulomas, necrosis, mucin, hemosiderin, crystals, nucleoli, and mitoses.
RESULTS: The accuracy of the identification of ten features on different types of displays did not significantly differ among the three types of \"fixed\" workplace displays. The highest accuracy was observed for the identification of neutrophils, eosinophils, plasma cells, granuloma, and mucin. On the other hand, a lower accuracy was observed for the identification of crystals, mitoses, necrosis, hemosiderin, and nucleoli. Participant pathologists and residents preferred the use of larger displays (>30″) with a higher pixel count, resolution, and luminance.
CONCLUSIONS: Most features can be identified using any display. However, certain features posed more challenges across the three fixed display types. Furthermore, the use of a remote personal consumer-grade display chosen according to the pathologists\' preference showed similar feature identification accuracy. Several factors of display characteristics seemed to influence pathologists\' display preferences such as the display size, color, contrast ratio, pixel count, and luminance calibration. This study supports the use of standard \"unlocked\" vendor-agnostic displays for clinical digital pathology workflow rather than purchasing \"locked\" and more expensive displays that are part of a digital pathology system.

BACKGROUND: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematopoietic stem cell disease with features of hemolytic anemia, thrombosis, and bone marrow failure. Due to intravascular hemolysis and hemoglobinuria, renal dysfunction is often accompanied in PNH patients.
METHODS: A 25-year old woman presenting gross hematuria after coronavirus disease 2019 infection was admitted to our medical center. She had mild nausea and headache. She was diagnosed with iron deficiency anemia few years ago and had no other underlying disease. Her laboratory findings showed acute kidney injury (AKI) and severe anemia, with evidences of hemolysis.
METHODS: Renal biopsy was done to determine the cause of renal failure and the result was acute tubular necrosis with deposition of golden pigments, hemosiderin. With pathologic result and laboratory finding of hemolysis, we did flow cytometry for PNH, and the patient was finally diagnosed with PNH.
METHODS: With AKI and oliguria, the patient started to take hemodialysis.
RESULTS: After taking 5 sessions of hemodialysis, the patient\'s renal function was recovered from AKI. With diagnosis of PNH, the patient is now being treated with complement C5 inhibitor.
CONCLUSIONS: This challenging case tells us that we should consider the first manifestation of PNH as a cause of severe AKI requiring hemodialysis in a patient with anemia and evidence of hemolysis.