A Retrospective Study of the Histopathological Spectrum of Erythema Nodosum Leprosum.

Background: There are no recent studies with a focus on the histopathology of erythema nodosum leprosum (ENL). Objectives: To describe the histopathological spectrum of ENL. Materials and Methods: Digital records from the pathology department were searched, and 125 slides were included. The histopathologic findings were recorded using a pre-designed proforma. Results: Several patterns were noted with the most common being a superficial and deep, perivascular and peri-appendageal, well-circumscribed dermal infiltrate that was seen in 70 (56.0%) biopsies. Other dermal patterns included a similar but loose infiltrate in 19 (15.2%) biopsies, diffuse dermal involvement in 9 (7.2%), top-heavy in 9 (7.2%), and bottom-heavy infiltrates in 12 (9.6%). Subcutaneous tissue was included in 107 biopsies. Extension of dermal infiltrates to the subcutis was noted in 71 (66.4%) biopsies and predominant involvement of the subcutis was noted in 6 (4.8%) biopsies, with lobular involvement in 60 (56.1%), septal involvement in 3 (2.8%), and septo-lobular involvement in 14 (13.1%). In 30 (28.0%) biopsies, the subcutaneous fat was uninvolved. The infiltrates contained neutrophils and foamy histiocytes in variable proportions, along with lymphocytes and plasma cells. Eosinophils were noted occasionally. Medium and/or small vessel vasculitis was noted in 11 (8.8%) biopsies. Fite-Faraco staining was available for 112 biopsies and revealed mainly fragmented and granular acid-fast bacilli (AFB) in 29 (25%) biopsies. Limitations: Our study had a retrospective design; we could not compare the lesional age and clinical characteristics of patients with the histological features. Conclusion: ENL is characterized by dermal infiltrates composed of foamy histiocytes and neutrophils in varying proportions arrayed in different dermal patterns. Extension of dermal infiltrates into the subcutis was frequent but absent in some. Predominant or exclusive involvement of the subcutis was rare. Vasculitis was noted in a small minority, while AFB were demonstrated in about a quarter of cases.

A Rare Cause of Pancytopenia From Lepromatous Leprosy Diagnosed in Bone Marrow Aspiration: A Bolt From the Blue.

Hansen's disease is caused by Mycobacterium leprae. The clinical presentation of lepromatous leprosy is broad, affecting patients with reduced T-cell immune response and causing anergy. Usually, the patient presents with numerous red to brown nodules over the face and auricles and is diagnosed by skin biopsy. We hereby report an unusual case of a 40-year-old man who presented with altered sensorium and fever. Lepromatous leprosy was diagnosed initially in the bone marrow aspiration without any clinical suspicion or previous skin biopsy confirmation. Bone marrow infiltration by lepra bacilli is very rare, with only a few cases reported in the literature so far.

Rosai-Dorfman Disease in a Middle-Aged Man With Recurrent Pleural Effusions and Lymphadenopathy.

Rosai-Dorfman disease (RDD) is a rare benign condition that presents most commonly with lymphadenopathy and skin lesions and is characterized by infiltration of histiocytes into the skin and soft tissues. We present a case of RDD in an Afro-Caribbean male in his 50s who presented to our chest clinic with shortness of breath, cough, and weight loss of 15 kg over one year. CT scan showed evidence of right pleural effusion, mediastinal and hilar lymphadenopathy, and bony lesions in the spine. Cytology from multiple pleural effusions and endobronchial ultrasound-guided fine needle aspiration from lymph nodes did not show any malignancy. Left axillary excisional biopsy showed a pattern consistent with RDD. The patient was started on interferon therapy by the hematologist and pleurodesis after repeated pleural taps failed to relieve recurrent right pleural effusions. This case emphasizes the importance of tissue diagnosis to avoid misdiagnosis and unnecessary treatment.

Unusual presentation of primary central xanthoma of the maxilla associated with impacted canine: An update on immunohistochemistry in the diagnosis.

A xanthoma is an extremely rare condition that affects the soft tissues and bones and is characterized by a predominance of lipid-rich foamy histiocytes. The onset of xanthomas is frequently accompanied by primary or secondary hyperlipidemia. Primary bone xanthomas are very uncommon benign bone lesions that are not linked to hyperlipidemia. Histopathologically, they are distinguished by histiocytes, an abundance of foam cells or xanthoma cells that contain lipids, and a paucity of multinucleated giant cells. There have only been four reports of primary maxillary xanthoma in the medical literature. We present a rare primary intrabony xanthoma of the anterior maxilla in a 23-year-old normolipidemic female patient with solitary radiolucency. Using CD68, S-100, and CD1a immunohistochemical staining, it is possible to distinguish between macrophage/non-Langerhans histiocytes and Langerhans histiocytes. Therefore, a diagnosis of a central xanthoma of the jaws must be made.

Clinicopathological diagnosis of Lennert lymphoma: a case report and review of the literature.

BACKGROUND: Lennert lymphoma (LL) is a variant of peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), also known as a lymphoepithelioid variant of PTCL. Because of the rarity and lack of clear-cut diagnostic criteria, LL is susceptible tomisdiagnosis. Although previously diagnosed with LL might be reclassified and evaluated with the advent of of molecular and/or genetic findings, cytomorphology and immunohistochemistry are still the key to give rise to correct diagnosis. CASE PRESENTATION: We report a case of a patient who was diagnosed as LL based on cytomorphology and immunohistochemistry. Routine stain (Hematoxlin and Eosin-H&E) revealed tumor cells were mainly small to medium-sized CD4(+) T cells, the CD8 +/TIA-1 + cytotoxic cells were less minority, no expressions of follicle helper T cell markers (CD10, BCL6, PD1, CXCL13, ICOS) or CD21(+) hyperplastic FDC network, or proliferation of high edndothelial venules were noted; however, numerous epithelioid histiocytes are noted in the background and scattered EBV(+) cells were also present. The patient was achieved complete remission after six courses of chemotherapy with cyclophosphamide, epirubicin, vincristine, etoposide, and prednisone regimen. She was followed for 5 years without recurrence or progression. CONCLUSIONS: Classic LL is not difficult to diagnose by cytomorphology and immunohistochemistry, and the mutation profiles can be helpful to distinguish LL from other lymphomas.

A Case of Two Diametrically Opposed Gastric Xanthomas in the Pyloric Antrum: An Unusual and Benign Endoscopic Finding.

Gastrointestinal tract xanthomas are rarely encountered findings in upper gastrointestinal endoscopy. They are non-tumor, well-demarcated, yellowish mucosal plaques most commonly diagnosed in the stomach, especially in the antrum or the pyloric region. Histologically, a gastric xanthoma consists of foamy histiocytes in the lamina propria. Although it is a benign lesion, it can be associated with various precancerous conditions and its appearance can resemble malignancy. We report the case of a 74-year-old female patient who presented to the outpatient clinic with a six-month history of intermittent pain in the epigastrium. The patient's physical examination as well as the hematological and biochemical investigations were normal. The upper gastrointestinal endoscopy revealed yellowish plaques in the pyloric antrum of the stomach, which were diagnosed as gastric xanthomas by histological examination. The significance of gastric xanthomas in relation to gastric disease still remains to be determined. Given the frequent association of gastric xanthomas and known premalignant lesions and occasionally malignant changes of the gastric mucosa, we need to pay close attention to endoscopic diagnosis and histochemical and immunohistochemical evaluation.

The Lone Lump: Cutaneous Rosai-Dorfman Disease as an Isolated Upper Arm Lesion.

Rosai-Dorfman disease (RDD) is a rare disorder characterized by excessive growth of histiocytes. We present a case of a 14-year-old female with cutaneous RDD who had a subcutaneous lump on her left arm for three years. The lump became tender and progressively larger over the past year. She had no systemic symptoms, and her physical examination revealed a mobile, tender lump. Laboratory tests were normal. Surgical excision of the lump was performed, and histopathological examination confirmed RDD with the presence of epithelioid histiocytes with eosinophilic and clear cytoplasm, along with emperipolesis and positive staining for CD68, CD163, S100, and OCT2. The patient was referred for follow-up and required no further treatment. RDD can present with subcutaneous masses without systemic symptoms, and it is important to consider RDD in the differential diagnosis of such cases. Surgical excision is the main treatment, and long-term monitoring is necessary due to the potential for disease recurrence. Awareness of cutaneous RDD presentations is crucial for accurate diagnosis and management.

Langerhans cell histiocytosis: unusual bone marrow infiltration-report of 2 cases in Ecuador.

Langerhans cell histiocytosis (LCH) is a histiocytic neoplasm characterized by the abnormal proliferation of Langerhans cells. Bone marrow (BM) involvement is associated with high-risk disease and poor survival. Although BM involvement is particularly uncommon, no reported cases of LCH with BM infiltration have been documented in Latin America until now. The aim of this report is to highlight the clinical, hematological, and BM findings of two cases of LCH with BM infiltration, providing insights that may aid in detecting suspected patients. We present two cases of LCH with BM infiltration. One case involved a 23-month-old male patient, and the other a 16-month-old female patient. Common clinical findings in both cases included hepatosplenomegaly and fever. Hematological findings revealed anemia in both cases. The key diagnostic tool was the BM biopsy, which revealed histiocyte nests with characteristic morphology, CD1a-positive cells, increased eosinophils, and reactive paratrabecular lymphocytes. This report underscores the significance of clinical profiles in predicting BM infiltration in LCH. The presence of histiocyte nests displaying the characteristic morphology of Langerhans cells, accompanied by an elevation in eosinophils, indicates bone marrow involvement. Furthermore, the demonstration of CD1a-positive cells through immunohistochemistry serves as a crucial diagnostic tool.

Cytoplasmic PPARγ Significantly Correlates With P53 Immunohistochemical Expression and Tumor Size in Localized Tenosynovial Giant Cell Tumor.

BACKGROUND: Tenosynovial giant cell tumor (TGCT) is a monoarticular fibrohistiocytic benign or locally aggressive soft tissue tumor that originates from the synovium of joints, bursae, and tendon sheaths. It has an inflammatory neoplastic nature, with a clinical presentation ranging from pain, swelling, stiffness, and limited range of movement to joint instability and blockage. Its uncommon incidence leads to a poorly understood pathogenesis. Localized forms of TGCT (LTGCT) can cause significant morbidity, interfere with daily patient activities, and decrease the patient's quality of life in challenging cases. This study aimed to investigate the immunohistochemical expression of PPARγ (peroxisome proliferator-activated receptor gamma) and P53 in LTGCT to understand the disease better and offer potential therapeutic targets. METHODS: The study is cross-sectional, in which 27 LTGCT cases were collected from the Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt. Solitary and multiple LTGCT cases retrieved between January 2018 and December 2022 were included, and immunohistochemically stained with anti-PPARγ and P53 antibodies. The TGCT samples were excluded if they were insufficient for sectioning, processing, and interpretation, over-fixed, had process artifacts, or were of the diffuse TGCT type. Scoring of stain expression was performed by ImageJ (National Institutes of Health, Bethesda, MD) analysis using the threshold method and was expressed in percent area/high power field. Clinicopathological correlations were analyzed. RESULTS: All the 27 collected LTGCT cases were located in the small joints of patients' hands. Cases with solitary LGTCTs constituted 55.6% (n = 15), while 44.4% (n = 12) had multiple LTGCTs related to one affected site/case (e.g., multiple tumors in one finger). PPARγ was expressed in the cytoplasm of mononuclear and multinucleated tumor cells and foamy histiocytes, while P53 expression was mainly in mononuclear cells' nuclei. PPARγ significantly correlated with P53 expression (r = 0.9 and P = 0.000). PPARγ (r = 0.4 and P = 0.02) and P53 (r = 0.5 and P = 0.01) were positively correlated with tumor size. Only P53 expression was positively correlated with tumor multiplicity (r = 0.4 and P = 0.03). Using the receiver operating characteristic curve test, the P53 cutoff score detecting the multiplicity of TGCTs was ≥20.5%, with a 75% sensitivity and 80% specificity. CONCLUSION: PPARγ and P53 have a significant role in LTGCT growth, while P53 plays a role in tumor multiplicity. They can be possible targets in LTGCTs unfit for excision.

Xanthogranulomatous pleuritis induced by recurrent biliothorax due to a biliopleural fistula: The first case report in the literature.

Xanthogranulomatous pleuritis is an extremely rare pathological entity, characterized by the infiltration of foamy cells and multinucleated giant cells within the pleural space. This condition often mimics infectious and neoplastic processes, presenting significant diagnostic challenges. This report details the first documented case of xanthogranulomatous pleuritis induced by recurrent biliothorax due to a biliopleural fistula, presenting a unique clinical scenario. We describe the clinical presentation, diagnostic hurdles, and both the surgical and medical management of this case. The discovery of biliothorax, evidenced by pleural fluid bilirubin levels that exceed serum bilirubin levels, underscores the importance of considering biliothorax in the differential diagnosis of recurrent pleural effusions, particularly in patients with a history of trauma. This case emphasizes the need for heightened awareness and a multidisciplinary approach in the diagnosis and treatment to effectively manage this complex condition and prevent recurrence.

Xanthogranulomatous pancreatitis: A rare entity in the spectrum of pancreatic lesions, a case report.

INTRODUCTION: Xanthogranulomatous pancreatitis (XGP) is a rare, benign, and idiopathic disease that often presents with non-specific symptoms and can mimic or coexist with other pancreatic diseases. Despite its infrequency, XGP is frequently misdiagnosed as a pancreatic neoplasm, with only 15 reported cases in the literature. The pathogenesis of XGP remains unclear. CASE REPORT: We present the case of a 34-year-old woman with no pathological history who experienced continuous abdominal pain and oral intolerance, without signs of cholestasis. An abdominal CT scan initially suggested a cystic neoplasm of the pancreas, leading to a laparotomic cephalic duodenopancreatectomy. The anatomopathological study and immunohistochemistry revealed XGP in association with a mucinous cystic neoplasm with mild to moderate atypia. The patient remained hospitalized for six days post-surgery without any complications. DISCUSSION: XGP may be induced by the inflammatory reaction secondary to the obstruction of the pancreatic duct by mucin. The etiology is unknown, but it is attributed to a combination of obstruction, hemorrhage, or ductal infection. Abdominal pain is the most common symptom. Differentiating XGP from malignant processes of the pancreatic gland is challenging. Surgical treatment typically involves the Whipple procedure; however, echoendoscopy with biopsy is now available for a more accurate and early differential diagnosis. CONCLUSION: XGP is a rare and challenging differential diagnosis for pancreatic neoplasms. Due to its potential to mimic malignant lesions, a high index of suspicion is necessary. Echoendoscopy with fine-needle aspiration biopsy should be considered a routine diagnostic tool before major surgery, such as the Whipple procedure.

Supranuclear Palsy as an Initial Presentation of the Adult-Onset Niemann-Pick Type C.

(1) Background: Niemann-Pick type C1 (NP-C1) is a lysosomal storage disorder that results in the defective trafficking of cholesterol and other cellular lipids in the endosomal-lysosomal pathway. This rare autosomal recessive disorder presents in three forms based on the age of onset. The adult form presents in patients greater than 15 years of age but is rarely seen after the age of 30. Common symptoms of the late adult-onset category of NP-C1 include progressive cognitive impairment and ataxia, with psychiatric and movement disorders presenting less frequently than in other forms of NP-C1. Dystonic movement disorders present most frequently, along with chorea, myoclonus, and parkinsonism. Herein, we present a rare case of NP-C1, diagnosed at age 35 with an initial symptom of supranuclear palsy. The goal of the presented case is to highlight the importance of the neurological examination and an inclusive differential diagnosis in patients with new-onset supranuclear palsy. (2) Methods: A single case report. (3) Results: A 46-year-old male with a past medical history of NP-C1 was admitted to the hospital for respiratory distress. He was noted to have a supranuclear gaze palsy with partially preserved voluntary saccades to the right. His mother revealed that he first had difficulty moving his eyes at the age of 34. After multiple consultations and genetic testing one year later, he was diagnosed with NP-C1. (4) Conclusions: Because NP-C1 affects many regions of the brain responsible for eye movements, neurological eye assessments can be a useful tool in diagnoses. Furthermore, eye movement abnormalities may be the initial presenting symptom of NP-C1, predisposing patients to misdiagnosis with progressive supranuclear palsy and other conditions that may mimic early-stage NP-C1. Definitive diagnosis is achieved through genetic testing. Filipin staining test was the gold standard in the past. The NP-C Suspicion Index was developed to assist in diagnoses, but its efficacy is unclear with late adult-onset NP-C1. Although no cure exists, early identification can facilitate an improved symptom management course for patients. Miglustat, a glucosylceramide synthase (GCS) inhibitor, is the approved therapy in Europe specific to NP-C1 for slowing and preventing the neurological manifestations of NP-C1. Delays between symptom onset and treatment initiation are likely to result in poorer outcomes and a progression of neurological symptoms. High doses may present tolerance concerns, especially in cases of delayed treatment and advanced neurological deficit.

Single-cell analysis of a progressive Rosai-Dorfman disease affecting the cerebral parenchyma: a case report.

Neurologic Rosai-Dorfman disease (RDD) is a rare type of non-Langerhans cell histiocytosis that affects the central nervous system. Most neurologic RDDs grow like meningiomas, have clear boundaries, and can be completely resected. However, a few RDDs are invasive and aggressive, and no effective treatment options are available because the molecular mechanisms involved remain unknown. Here, we report a case of deadly and glucocorticoid-resistant neurologic RDD and explore its possible pathogenic mechanisms via single-cell RNA sequencing. First, we identified two distinct but evolutionarily related histiocyte subpopulations (the C1Q+ and SPP1+ histiocytes) that accumulated in the biopsy sample. The expression of genes in the KRAS signaling pathway was upregulated, indicating gain-of-function of KRAS mutations. The C1Q+ and SPP1+ histiocytes were highly differentiated and arrested in the G1 phase, excluding the idea that RDD is a lympho-histio-proliferative disorder. Second, although C1Q+ histiocytes were the primary RDD cell type, SPP1+ histiocytes highly expressed several severe inflammation-related and invasive factors, such as WNT5A, IL-6, and MMP12, suggesting that SPP1+ histiocytes plays a central role in driving the progression of this disease. Third, oligodendrocytes were found to be the prominent cell type that initiates RDD via MIF and may resist glucocorticoid treatment via the MDK and PTN signaling pathways. In summary, in this case, we report a rare presentation of neurologic RDD and provided new insight into the pathogenic mechanisms of progressive neurologic RDD. This study will also offer evidence for developing precision therapies targeting this complex disease.

Neuropathological assessment of the olfactory bulb and tract in individuals with COVID-19.

The majority of patients with Parkinson disease (PD) experience a loss in their sense of smell and accumulate insoluble α-synuclein aggregates in their olfactory bulbs (OB). Subjects affected by a SARS-CoV-2-linked illness (COVID-19) also frequently experience hyposmia. We previously postulated that microglial activation as well as α-synuclein and tau misprocessing can occur during host responses following microbial encounters. Using semiquantitative measurements of immunohistochemical signals, we examined OB and olfactory tract specimens collected serially at autopsies between 2020 and 2023. Deceased subjects comprised 50 adults, which included COVID19 + patients (n = 22), individuals with Lewy body disease (e.g., PD; dementia with Lewy bodies (n = 6)), Alzheimer disease (AD; n = 3), and other neurodegenerative disorders (e.g., progressive supranuclear palsy (n = 2); multisystem atrophy (n = 1)). Further, we included neurologically healthy controls (n = 9), and added subjects with an inflammation-rich brain disorder as neurological controls (NCO; n = 7). When probing for microglial and histiocytic reactivity in the anterior olfactory nuclei (AON) by anti-CD68 immunostaining, scores were consistently elevated in NCO and AD cases. In contrast, microglial signals on average were not significantly altered in COVID19 + patients relative to healthy controls, although anti-CD68 reactivity in their OB and tracts declined with progression in age. Mild-to-moderate increases in phospho-α-synuclein and phospho-tau signals were detected in the AON of tauopathy- and synucleinopathy-afflicted brains, respectively, consistent with mixed pathology, as described by others. Lastly, when both sides were available for comparison in our case series, we saw no asymmetry in the degree of pathology of the left versus right OB and tracts. We concluded from our autopsy series that after a fatal course of COVID-19, microscopic changes in the rostral, intracranial portion of the olfactory circuitry -when present- reflected neurodegenerative processes seen elsewhere in the brain. In general, microglial reactivity correlated best with the degree of Alzheimer's-linked tauopathy and declined with progression of age in COVID19 + patients.

Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy.

Histiocytic neoplasms are diverse clonal haematopoietic disorders, and clinical disease is mediated by tumorous infiltration as well as uncontrolled systemic inflammation. Individual subtypes include Langerhans cell histiocytosis (LCH), Rosai-Dorfman-Destombes disease (RDD) and Erdheim-Chester disease (ECD), and these have been characterized with respect to clinical phenotypes, driver mutations and treatment paradigms. Less is known about patients with mixed histiocytic neoplasms (MXH), that is two or more coexisting disorders. This international collaboration examined patients with biopsy-proven MXH with respect to component disease subtypes, oncogenic driver mutations and responses to conventional (chemotherapeutic or immunosuppressive) versus targeted (BRAF or MEK inhibitor) therapies. Twenty-seven patients were studied with ECD/LCH (19/27), ECD/RDD (6/27), RDD/LCH (1/27) and ECD/RDD/LCH (1/27). Mutations previously undescribed in MXH were identified, including KRAS, MAP2K2, MAPK3, non-V600-BRAF, RAF1 and a BICD2-BRAF fusion. A repeated-measure generalized estimating equation demonstrated that targeted treatment was statistically significantly (1) more likely to result in a complete response (CR), partial response (PR) or stable disease (SD) (odds ratio [OR]: 17.34, 95% CI: 2.19-137.00, p = 0.007), and (2) less likely to result in progression (OR: 0.08, 95% CI: 0.03-0.23, p < 0.0001). Histiocytic neoplasms represent an entity with underappreciated clinical and molecular diversity, poor responsiveness to conventional therapy and exquisite sensitivity to targeted therapy.

Clinicopathological study of ophthalmic cutaneous and mucocutaneous non-langerhans cell histiocytic lesions.

BACKGROUND: The "C group" of the histiocytic disorders is characterized by non-Langerhans-cell histiocytic lesions in the skin, mucosal surfaces, or both, out of which Juvenile xanthogranuloma (JXG) is the most common typically affecting the skin. The eye is the most common extra-cutaneous site of JXG., we aim at providing our clinical and histopathological experience with this group of diseases including the adult-onset xanthogranuloma (AXG). METHODS: This is a retrospective cohort study of all patients with the tissue diagnosis of ocular and periocular cutaneous and mucocutaneous non-LCH disorders who presented to us over a period of 25 years (January 1993 to December 2018). RESULTS: Twenty patients were diagnosed as "Group C" disease with an age range of 2 months-60.9 years. Eleven patients were females (55%) and nine were males (45%). The involvement was mostly unilateral in 80.9%. All cases fell into the xanthogranuloma family with 11 JXG patients, 8 AXG patients of skin and ocular surface, and one patient with solitary reticulohistiocytoma (SRH). The clinical site of involvement in JXG was primarily in the eyelid in 5 patients (45%), ocular surface lesions in 2 (18%), iris in 2 (18%), choroidal and bilateral orbital lesions in 1 patient each (9%). The group of AXG, presented equally with eyelid lesions in 4/8 and ocular surface lesions in 4/8. The non-Langerhans' histiocytic infiltrate showed supportive immunohistochemical staining properties (reactive to CD68 marker and negative to S-100 and langerin markers). CONCLUSION: Among the rare histiocytic disorders, xanthogranulomatosis is the commonest and has wide clinical manifestations. Accurate diagnosis needs to be supported by typical histopathological findings. JXG was the commonest in our study with relatively older mean age at presentation and frequent eyelid rather than iris involvement. AXG is often confused with xanthelasma when involving the eyelids with corneal limbal involvement is relatively frequent.

Extranodal Rosai-Dorfman Disease: a rare presentation involving anterior chest wall in a middle-aged female.

Rosai-Dorfman Disease is a rare benign disorder involving overproduction of immune cells, causing swollen lymph nodes and, in rare cases, the sternum. The sternal involvement may cause chest pain and masses. Diagnosis is confirmed through clinical examination, biopsy, and imaging. Treatment options may include surgery, radiation, or steroids. In this case study, we present an unusual example of extranodal Rosai-Dorfman Disease involving the sternum, bilateral clavicles and first three ribs, and pectoral muscle with no associated lymphadenopathy or systemic symptoms in a 57-year-old female. The etiology, pathology, immunohistochemistry, imaging findings, and treatment options of this unique disease are discussed.

Facial Cutaneous Rosai-Dorfman Disease: Dermoscopic Findings with Successful Surgical Treatment.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytosis characterized by an accumulation of activated histiocytes within the affected tissues. It is a heterogeneous disease that includes the classical (nodal) and extra-nodal variants. The cutaneous form of the disease without the characteristic lymphadenopathy is rare and is often misdiagnosed as other dermatologic diseases. Misdiagnosis as lymphoproliferative and infectious diseases such as lymphoma and tuberculosis have been reported in the literature. Herein, we report a case of facial cutaneous RDD with successful surgical treatment. In addition, we provide dermoscopic findings and literature review as dermoscopy can be a useful adjuvant tool in the diagnosis of cutaneous RDD.

Xanthogranulomatous inflammation of the lower jaw bone: a rare case report.

Xanthogranulomatous inflammation (XGI) is an uncommon type of chronic inflammation and is histologically characterized by foamy histiocytes and giant cells. The most common sites of occurrence are kidneys and gallbladder. The etiology remains controversial. Involvement of the lower jaw bone is rare. In this study, we report a case of XGI presenting in the lower jaw.