Cutaneous reactive lymphoid proliferation (CRLP) is a condition that resembles cutaneous lymphoma, and differentiating the two is necessary for proper diagnosis and treatment. It can be idiopathic or caused by viruses, drugs, or skin trauma, resulting in reactive lymphoid hyperplasia. Several clinical and histopathological features are helpful for differentiating CRLP from lymphoma, and they must be considered as a whole to reach the correct diagnosis. The number, location, and progression of CRLP lesions are important clinical clues, while the type, size, arrangement, surface markers, and clonality of the cellular infiltrate are key histopathological clues. We present a case in which CRLP arose in the setting of concomitant antidepressant and antihypertensive use, which are both potential causes of CRLP. In this case, excision served as both diagnosis and treatment. The benign presentation and lack of clonality led to the diagnosis of CRLP. While the cause is unknown, drug exposure was a possible inciting factor, and the patient will be monitored for recurrence.

While ex vivo confocal laser scanning microscopy has previously demonstrated its utility in most common skin diseases, its use in the assessment of dermatological entities with lower incidence remains unexplored in most cases. We therefore aimed to evaluate the diagnostic efficacy of some rare skin tumors as well as a few inflammatory skin diseases, that have not yet been studied in ex vivo confocal laser scanning microscopy. A total of 50 tissue samples comprising 10 healthy controls, 10 basal cell carcinoma, 10 squamous cell carcinoma, and 20 rare skin conditions were imaged using the newest generation ex vivo confocal microscopy (Vivascope 2500 M-G4, Vivascope GmbH, Munich, Germany). Three blinded investigators were asked to identify characteristic features of rare skin disorders and distinguish them from more common skin diseases in the ex vivo confocal microscopy images. Our findings present the capability of ex vivo confocal microscopy to display distinctive morphologic patterns in common and rare skin diseases. As might be expected, we found a strong correlation between imaging experience and diagnostic accuracy. While the imaging inexperienced dermatohistopathologist reached 60% concordance, the imaging-trained dermatologist obtained 88% agreement with dermatohistopathology. The imaging-trained dermatohistopathologist achieved concordance up to 92% with gold-standard dermatohistopathology. This study highlights the potential of ex vivo confocal laser scanning microscopy as a promising adjunct to conventional dermatohistopathology for the early and precise identification of rare dermatological disorders.

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A 53-year-old female with primary biliary cholangitis was referred for the evaluation of a hepatic nodule identified during routine imaging. Ultrasonography revealed a homogeneous, hypoechoic, 18 mm nodule in segment 3 of the liver. On dynamic CT and MRI, the nodule showed mild enhancement at the hepatic artery-dominant phase. On diffusion-weighted images, the nodule exhibited pronounced hyperintensity with accompanying wedge-shaped perinodular hyperintensity (comet and comet-tail appearance). The nodule showed a portal perfusion defect on CT during arterial portography, and mild enhancement on CT during hepatic arteriography (CTHA). A nodular and wedge-shaped perinodular enhancement (comet and comet-tail appearance) in the CTHA was also clearly observed. The nodule demonstrated abnormal FDG uptake on 18F-FDG-PET/CT. An excisional biopsy was performed for histopathological diagnosis, and the nodule was diagnosed as reactive lymphoid hyperplasia (RLH). Diagnosing hepatic RLH by imaging is challenging due to its imaging findings overlapping with those of various malignant tumors, especially the nodular type of lymphomas, making differentiation particularly difficult. However, radiologists should note the perinodular early enhancement and the perinodular hyperintensity on diffusion weighted images, which are thought to be key imaging findings of RLH, along with other characteristics such as a single, small, homogeneous nodule with mild early enhancement and marked restricted diffusion. We propose to name the nodular lesion with perinodular early enhancement/hyperintensity on diffusion weighted images as \'comet and comet-tail appearances\'.

Pseudolymphoma is a reactive process involving lymphadenopathy, polyclonal proliferation of B or T-cells, simulating oral lymphoma. With its incidence being very rare, only four cases have been reported in oral cavity with the detailed immunocytochemical examination, which can be due to this entity\'s unawareness, underdiagnosis or overdiagnosis. It is prerogative to perform immunocytochemical investigations to prevent overdiagnosis as lymphoma, which can be debilitating to the patient. Wherein the treatment of pseudolymphoma initially includes topical or intralesional corticosteroid, antibiotics to surgical and radiotherapy based on its etiology. Herein, we discuss B-cell follicular lymphoid hyperplasia previously diagnosed as small round cell tumor.

Follicular lymphoid hyperplasia is a rare reactive benign lesion of the oral mucosa. This is also known as pseudolymphoma as the features mimic the malignant counterpart Follicular lymphoma. In present case, a 34 year old male patient came with a nodular swelling in the posterior-lateral left side of tongue. Medical or dental history was non contributory. Swelling was painless, well demarcated, and about peanut sized. The swelling was provisionally diagnosed as either neurilemmoma, mucocele, or traumatic fibroma. Complete excision was performed, and tissue was sent to a private laboratory. Histopathological findings seen were germinal centers having a core of monotonous cells of the same size and demarcated mantle area mimicking the lymphoma. Immunophenotyping revealed diffused positivity for kappa and lambda expressions. CD10 was diffusely positive in germinal centers and BCl 2 was positive in the mantle area while negative in germinal centers. The final diagnosis given was follicular lymphoid hyperplasia. The entity mentioned in the present paper is an unusual variant of the benign lymphoproliferative lesion and very few cases are reported in the tongue area. Thus, it is important to understand the nature of this benign lesion in all aspects to avoid diagnostic dilemmas due to its malignant mirroring characteristics.

Hepatic reactive lymphoid hyperplasia is an uncommon benign condition, often found incidentally as a solitary liver lesion. The chronic inflammatory reaction associated with autoimmune conditions and malignancies has been postulated as a possible aetiology. The diagnosis is challenging as it often mimics various malignancies radiologically and histologically, hence the diagnosis being made only after surgical resection. Lymphadenopathy is common with primary biliary cholangitis, though rarely reported with reactive lymphoid hyperplasia. We report a case of hepatic reactive lymphoid hyperplasia associated with portacaval lymphadenopathy in a patient with primary biliary cholangitis, diagnosed after surgical resection. We propose lesional biopsy be considered in patients with primary biliary cholangitis found to have a solitary lesion with supporting low-risk clinical and radiological features.

BACKGROUND: Primary cutaneous CD4+ small/medium-sized pleomorphic T-Cell lymphoproliferative disorder (PC-SMTLD) has been considered as a controversial dermatological disease that has been included in cutaneous T-cell lymphoma group, presenting most commonly as a solitary nodule and/or plaque with a specific and characteristic head and neck predilection. Due to the considerable overlap between PC-SMTLD and pseudolymphoma (PL), the differential diagnosis is often challenging. Methylation of DNA at position 5 of cytosine, and the subsequent reduction in intracellular 5-hydroxymethylcytosine (5-hmC) levels, is a key epigenetic event in several cancers, including systemic lymphomas. However, it has rarely been studied in cutaneous lymphomas.
OBJECTIVE: The authors aimed to explore the role of differential 5-hmC immunostaining as a useful marker to distinguish PC-SMTLD from PL.
METHODS: Retrospective case series study with immunohistochemical and immunofluorescence analysis of 5-hmC was performed in PL and PC-SMTLD.
RESULTS: Significant decrease of 5-hmC nuclear staining was observed in PC-SMTLD when compared with PL (p < 0.0001). By semi-quantitative grade integration, there were statistical differences in the final 5-hmC scores in the two study groups. The IF co-staining of 5-hmC with CD4 revealed a decrease of 5-hmC in CD4+ lymphocytes of PC-SMTLD.
CONCLUSIONS: The small clinical sample size of the study.
CONCLUSIONS: The immunorreactivity of 5-hmC in CD4+ lymphocytes was highly suggestive of a benign process as PL. Furthermore, the decrease of 5-hmC nuclear staining in PC-SMTLD indicated its lymphoproliferative status and helped to make the differential diagnosis with PL.

BACKGROUND: Immune inflammatory responses play an important role in spinal cord injury (SCI); however, the beneficial and detrimental effects remain controversial. Many studies have described the role of neutrophils, macrophages, and T lymphocytes in immune inflammatory responses after SCI, although little is known about the role of B lymphocytes, and immunosuppression can easily occur after SCI.
METHODS: A mouse model of SCI was established, and HE staining and Nissl staining were performed to observe the pathological changes. The size and morphology of the spleen were examined, and the effects of SCI on spleen function and B cell levels were detected by flow cytometry and ELISA. To explore the specific mechanism of immunosuppression after SCI, B cells from the spleens of SCI model mice were isolated using magnetic beads and analyzed by 4D label-free quantitative proteomics. The level of inflammatory cytokines and iron ions were measured, and the expression of proteins related to the Tom20 pathway was quantified by western blotting. To clarify the relationship between iron ions and B cell pyroptosis after SCI, we used FeSO4 and CCCP, which induce oxidative stress to stimulate SCI, to interfere with B cell processes. siRNA transfection to knock down Tom20 (Tom20-KD) in B cells and human B lymphocytoma cell was used to verify the key role of Tom20. To further explore the effect of iron ions on SCI, we used deferoxamine (DFO) and iron dextran (ID) to interfere with SCI processes in mice. The level of iron ions in splenic B cells and the expression of proteins related to the Tom20-Bax-caspase-gasdermin E (GSDME) pathway were analyzed.
RESULTS: SCI could damage spleen function and lead to a decrease in B cell levels; SCI upregulated the expression of Tom20 protein in the mitochondria of B cells; SCI could regulate the concentration of iron ions and activate the Tom20-Bax-caspase-GSDME pathway to induce B cell pyroptosis. Iron ions aggravated CCCP-induced B cell pyroptosis and human B lymphocytoma pyroptosis by activating the Tom20-Bax-caspase-GSDME pathway. DFO could reduce inflammation and promote repair after SCI by inhibiting Tom20-Bax-caspase-GSDME-induced B cell pyroptosis.
CONCLUSIONS: Iron overload activates the Tom20-Bax-caspase-GSDME pathway after SCI, induces B cell pyroptosis, promotes inflammation, and aggravates the changes caused by SCI. This may represent a novel mechanism through which the immune inflammatory response is induced after SCI and may provide a new key target for the treatment of SCI.

T-cell-rich angiomatoid polypoid pseudolymphoma (TRAPP) is a rare and recently defined entity, conceptualized just over a decade ago. Recognition of TRAPP is important because it can be clinically and microscopically confused with low-grade cutaneous lymphomas and other vascular proliferations. We report a case of a 28-year-old male with a solitary 1.2 cm red polypoid papule on the middle posterior base of the neck. The histopathological examination revealed a well-circumscribed dermal nodular proliferation of banal-appearing lymphovascular spaces with plump endothelial cells. Immunohistochemical analysis showed a T-cell-rich infiltrate. The clinical-pathological differential diagnosis for TRAPP includes pyogenic granuloma, angiolymphoid hyperplasia (epithelioid hemangioma), acral pseudolymphomatous angiokeratoma of children, cutaneous lymphoid hyperplasia, and low-grade cutaneous lymphomas and lymphoproliferative disorders. We review the literature and discuss the key differentiating features between TRAPP and its common differential diagnoses.