Search Results (119)

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms characterized by perivascular epithelioid cell proliferation. They can occur in various organs, but colonic PEComas are exceptionally rare, showing diagnostic challenges due to their nonspecific clinical presentation and similar features to those of other colorectal tumors. We present a case of a 61-year-old female with defecation accompanied by blood clots, initially diagnosed with a suspected tumor in the sigmoid colon. Despite initial biopsy yielding non-informative material, repeat colonoscopy and imaging studies revealed a malignant tumor with multinucleated giant (osteoclast-like) cells and probable p53 mutation, most likely of mesenchymal origin. Robotic surgical resection was performed, and ultimately pathological examination refined the diagnosis as a malignant PEComa of the colon. This case demonstrates the importance of considering PEComa in the differential diagnosis of colonic tumors. Further research is needed to ascertain the clinical behavior and optimal treatment for colonic PEComas. Full article

A 71-year-old Caucasian woman presented with lesions on both elbows. A physical examination revealed arcuate plaques with raised erythematous edges and central clearing. Comedones and cysts were evident on the border of the lesions. The dermatoscopic view showed the presence of pores, in addition to granuloma annulare changes. The biopsies showed changes according to granuloma annulare, but the granulomas were closely related to comedones and cysts. Furthermore, the presence of elastophagocytosis via multinucleated Langhans-type giant cells was evident. Verhoeff–van Gieson staining highlighted the transepithelial elimination of elastic fibers in the bottom of some cysts. The presence of comedones or cysts is exceptional in granuloma annulare. Only four similar cases have been reported. Although all previous cases showed lesions in sun-exposed areas over photodamaged skin, only our case showed transepithelial elimination of elastic fibers. Diabetes mellitus (DM) could play a role in the pathogenesis of this variant of actinic granuloma annulare, because most cases are associated with uncontrolled DM and the lesions improve after DM is controlled. Full article

Background/Objectives: The structural integrity and strength of the transgingival soft tissue seal around dental implant surfaces remain critical challenges. Therefore, animal models should include all three implant/tissue interfaces: bone, connective tissue, and epithelium. Thus, we sought to explore the rabbit mandibular diastema as a site for candidate intra-oral implant placement. Methods: Ninety-six custom mini-implants (with one of four different surfaces: machined, acid-etched, and with or without a nanotube coating) made from titanium 6/4 alloy were placed in the mandibular diastemas of twenty-four 16-week-old New Zealand white rabbits, with the implant collar above the alveolar crest. After 7, 21, and 42 days, the bony and connective tissue/implant interfaces were examined by light and scanning electron microscopy (SEM). Results: Of ninety-six implants, eight implants were found exposed to the oral cavity, with no evidence of soft tissue inflammation, suggesting that transmucosal implant placement would have been feasible. No significant differences were observed in collagen fiber orientation and fibrous tissue thickness by polarized light microscopy. However, SEM images showed that at all three time points, topographically complex nanotube surfaces had a profound effect on soft tissue peri-implant deposition, although functionally oriented collagen fibers were not identified attached to the implant surface. These surfaces also showed reparative peri-implant bone in the collar region. An intramembranous form of de novo bone formation was observed, together with tartrate-resistant acid-phosphatase-positive osteoclasts and multinucleate giant cells in the peri-implant endosseous compartment. Conclusions: Our results demonstrate that the rabbit mandibular diastema provides an intra-oral method of implant placement without the necessity of an extra-oral approach, tooth extractions, or bone augmentation procedures. Furthermore, given that three implant tissue interfaces can potentially be studied (bone, connective tissue, and epithelium) this model provides advantages over more traditional implant placement sites in the appendicular skeleton. Full article

Osteoclasts (OCs) are important therapeutic targets in the treatment of osteoporosis. The aim of this study was to explore a novel therapeutic approach for osteoporosis using Arcyriaflavin A (ArcyA), a natural compound derived from the marine invertebrate Eudistoma sp. We systematically evaluated the effects of ArcyA on OC differentiation and function in mouse models using molecular biology assays, cellular function analyses and in vivo animal experiments. We also evaluated the efficacy of ArcyA in human cells. The TRAP staining results provide the first clear evidence of the drug’s inhibitory effect, whereby the administration of ArcyA led to a significant reduction in TRAP-positive cells compared to the control group at concentrations that were non-toxic to bone marrow macrophages. Meanwhile, a significant reduction in the number of multinucleated giant cells with more than ten nuclei was observed. Furthermore, similar TRAP staining results were reproduced in human OCs, suggesting that ArcyA has the same effect on OCs derived from human PBMCs. At the molecular level, ArcyA treatment resulted in the downregulation of genes relevant to OC differentiation (NFATc1, cFos and TNFrsf11α), fusion and survival (DCstamp and ATP6v0d2) and resorption function (CTSK, MMP9, integrin β3 and ACP5). A western blot analysis of the corresponding proteins (NFATc1, cFos, CTSK and integrin β3) further confirmed the PCR results. Furthermore, ArcyA-treated OCs produced significantly fewer resorption pits, indicating suppressed bone resorption activity. Consistent with this, in vivo experiments using an ovariectomy (OVX)-induced osteoporosis mouse model showed that ArcyA treatment significantly alleviated bone loss. Mice in the treatment groups had higher BV/TV values, and this therapeutic effect was enhanced in a dose-dependent manner. In addition, our research also showed that IκB could be a potential target for the inhibitory effect of ArcyA. In conclusion, these findings suggest that ArcyA has significant therapeutic potential for the treatment of osteoporosis by inhibiting osteoclastogenesis and bone resorption. Further studies are warranted to explore its clinical applications. Full article

Giant cell tumor of bone (GCTb), formerly also known as osteoclastoma, is a pathological entity that in veterinary medicine is still undefined and, probably, underdiagnosed. In humans, GCTb is recognized as a primary benign bone tumor, locally aggressive, with high local recurrence rates, with controversial histogenesis that can rarely progress or present as a malignant form. In pets, this tumor is still considered rare, though the possibility of underdiagnosis is significant. Hence, the aim of the present study is to provide a histological and immunohistochemical characterization of a small case series of presumptive feline GCTb, comparing our results to the data reported for the human counterpart. Searching our archive, we found, from 2010 to 2023, only three diagnosed cases of GCTb from domestic cats (felis catus). After diagnosis revision, the samples were submitted to immunohistochemistry for Iba1, TRAP, SATB2, RUNX2, RANK, karyopherin α2 (KPNA-2), and osteocalcin. Ki-67 index was also evaluated. Results showed that the multinucleated giant cells were positive for Iba1, TRAP, and RANK, accounting for their osteoclastic origin. On the other side, mononuclear cells were mostly positive for osteoblast markers such as RUNX2, SATB2, and KPNA-2, whereas tumor-associated macrophages showed positivity for Iba1. Hence, results on the cell types characterizing the feline GCTb were comparable to those described in the human form of the tumor. Currently, diagnostic criteria for GCTBs in cats and, in domestic animals more broadly, are still lacking. This study provides valuable data into the immunohistochemical characteristics of the cell populations in feline GCTBs, enhancing veterinarians’ and pathologists’ knowledge for its diagnosis, ultimately improving patient care. Larger case series, complete with follow-up information, molecular analyses for specific mutations, and imaging of both tumors and patients, are needed to improve identification and achieve greater sensitivity in diagnosing this unique tumor. Full article

In vitro models serve as valuable tools for understanding the complex cellular and molecular interactions involved in granuloma formation, providing a controlled environment to explore the underlying mechanisms of their development and function. Various models have been developed to replicate granulomatous diseases, even though they may lack the sophistication needed to fully capture the variability present in clinical spectra and environmental influences. Traditional cultures of PBMCs have been widely used to generate granuloma models, enabling the study of aggregation responses to various stimuli. However, growing cells on a two-dimensional (2D) plastic surface as a monolayer can lead to altered cellular responses and the modulation of signaling pathways, which may not accurately represent in vivo conditions. In response to these limitations, the past decade has seen significant advancements in the development of three-dimensional (3D) in vitro models, which more effectively mimic in vivo conditions and provide better insights into cell–cell and cell–microenvironment interactions. Meanwhile, the use of in vivo animal models in biomedical research must adhere to the principle of the three Rs (replacement, reduction, and refinement) while ensuring that the models faithfully replicate human-specific processes. This review summarizes and compares the main models developed to investigate granulomas, focusing on their contribution to advancing our understanding of granuloma biology. We also discuss the strengths and limitations of each model, offering insights into their biological relevance and practical applications. Full article

Cutaneous silica granulomas are a form of foreign-body granulomatous reactions. They are characterized histopathologically by sarcoidal granulomas in association with silica crystals. Asteroid bodies, a classical histopathological feature of sarcoidosis, have not previously been reported in association with silica granulomas. Herein, we present the case of an 83-year-old man with an asymptomatic papule on the vertex scalp. Histopathology revealed a dermal granulomatous reaction to silica crystals. Asteroid bodies were observed in the cytoplasm of multinucleated giant cells. In the absence of systemic symptoms or laboratory findings suggestive of sarcoidosis, a final diagnosis of silica granuloma with asteroid bodies was made. While they have been observed in several other granulomatous reactions, the present case represents a novel association of asteroid bodies with silica granulomas. Full article

Background: Giant cell tumor of bone (GCTB) is a locally aggressive tumor. It accounts for only 5% of all bony tumors. Early diagnosis, and follow-up for recurrence is often difficult due to a lack of biogenetic markers. Giant cells are multinucleated epithelioid cells derived from macrophages. Histologically, giant cells are also present in other pathologies of bone, e.g., aneurysmal bone cyst, chondroblastoma, giant cell granuloma, and malignant giant cell tumor, etc. Similarly, radiographic findings overlap with other osteolytic lesions, making the diagnosis and prognosis of giant cell tumor very challenging. Aims and Objectives: The purpose of this study was to explore biological and genetic markers which can be used for detection, differentiation, recurrence, and prognosis of GCTB. This will help to better understand the clinical outcome of GCTB and minimize the need for interventions. Methods: We conducted a literature search using Google, Google Scholar, PubMed, Wiley Library, Medline, Clinical trials.org, and Web of Science. Our search strategy included MeSH terms and key words for giant cell tumor and biogenetic markers from date of inception to September 2020. After excluding review articles, 246 duplicates, and non-relevant articles, we included 24 articles out of 1568 articles, summarizing the role of biogenetic markers in the prognosis of GCT. Results: P63 is 98.6% sensitive and relatively specific for GCT as compared to other multinucleated giant cells containing neoplasms. MDM2 (mouse double minute 2 homolog), IGF1 (insulin-like growth factor 1), STAT1 (signal transducer and activator of transcription 1), and RAC1 (Ras-related C3 botulinum toxin substrate 1) are associated with GCTB recurrence, and might serve as biomarkers for it. Increased expression of the proteins STAT5B, GRB2, and OXSR1 was related to a higher probability of metastasis. H3F3A and H3F3B mutation analysis appears to be a highly specific, although less sensitive, diagnostic tool for the distinction of giant cell tumor of bone (GCTB) and chondroblastoma from other giant cell-containing tumors. A neutrophil to lymphocyte ratio (NLR) > 2.70, platelet to lymphocyte ratio (PLR) > 215.80, lymphocyte to monocyte ratio (LMR) ≤ 2.80, and albumin to globulin ratio (AGR) < 1.50 were significantly associated with decreased disease-free survival (DFS) (p < 0.05). Large amounts of osteoclast-related mRNA (cathepsin K, tartrate-resistant acid phosphatase, and matrix metalloproteinase9) in GCTs (p < 0.05) are associated with the grade of bone resorption. We propose that subarticular primary malignant bone sarcomas with H3.3 mutations represent true malignant GCTB, even in the absence of a benign GCTB component. IMP3 and IGF2 might be potential biomarkers for GCT of the spine in regulating the angiogenesis of giant cell tumor of bone and predicting patients’ prognosis. Conclusions: This review study shows serological markers, genetic factors, cell membrane receptor markers, predictive markers for malignancy, and prognostic protein markers which are highly sensitive for GCT and relatively specific for giant cell tumor. MDM2, IGF1, STAT1, RAC1 are important makers in determining recurrence, while P63 and H3F3A differentiate GCT from other giant cell-containing tumors. STAT5B, GRB2, and OXSR1 are significant in determining the prognosis of GCT. Apart from using radiological and histological parameters, we can add them to tumor work-up for definitive diagnosis and prognosis. Full article

Feline injection-site sarcomas (FISSs) are malignant skin tumors of mesenchymal origin arising at local post-vaccination (or injection) sites. In recent years, a fluorescence imaging technique based on probes targeting α_vβ₃ integrin has been effectively applied for the surgical complete resection of the tumor. In our study, we investigated the utility of a commercially available anti-α_v integrin polyclonal antibody for the histopathological evaluation of FISS’s surgical excision margins. We collected 10 formalin-fixed paraffin-embedded (FFPE) feline excisional biopsies with a histopathological diagnosis of FISS (7 fibrosarcomas and 3 pleomorphic sarcomas) and wide margin tissue, along with one subcutaneous injection-site granuloma and 6 osteosarcomas. Samples were processed for histology, and slides were stained for IHC with the anti-α_v integrin antibody. Immunostained slides were evaluated for the cellular localization and intensity of the staining in different neoplastic and non-neoplastic cell populations. Neoplastic and non-neoplastic spindle cells had cytoplasmic positivity in all fibrosarcomas. Inflammatory cells, including macrophages of the injection-site granuloma, were negative. Multinucleated giant cells in the pleomorphic sarcomas had an intense membranous positivity. Although the anti-α_v integrin antibody was ineffective for the histopathological evaluation of surgical excision margins, the membranous localization of α_v integrin in multinucleated giant cells of pleomorphic sarcomas suggests that it plays a role in the oncogenesis of this FISS variant. Full article

Osteoclasts are bone-resorbing multinucleated giant cells formed by the fusion of monocyte/macrophage lineages. Various small GTPases are involved in the multinucleation and differentiation of osteoclasts. However, the roles of small GTPases regulatory molecules in osteoclast differentiation remain unclear. In the present study, we examined the role of Dennd2c, a putative guanine nucleotide exchange factor for Rab GTPases, in osteoclast differentiation. Knockdown of Dennd2c promoted osteoclast differentiation, resorption, and expression of osteoclast markers. Morphologically, Dennd2c knockdown induced the formation of larger osteoclasts with several protrusions. In contrast, overexpression of Dennd2c inhibited the multinucleation and differentiation of osteoclasts, bone resorption, and the expression of osteoclast markers. Dennd2c-overexpressing macrophages exhibited spindle-shaped mononuclear cells and long thin protrusions. Treatment of Dennd2c-overexpressing cells with the Cdc42 inhibitor ML-141 or the Rac1 inhibitor 6-thio-GTP prevented protrusion formation. Moreover, treatment of Dennd2c-overexpressing cells with the actin polymerization inhibitor latrunculin B restored multinucleated and TRAP-positive osteoclast formation. These results indicate that Dennd2c negatively regulates osteoclast differentiation and multinucleation by modulating protrusion formation in macrophages. Full article

Background/Objectives: Myocarditis is an inflammatory disease of the myocardium and remains to this day a challenging diagnosis. A promising novel imaging method uses the expression of somatostatin receptors (SSTRs) on inflammatory cells to visualize myocardial inflammation. However, little is known about the histopathological correlate of SSTR imaging in different forms of myocarditis. Methods: In the present retrospective histopathological study, we systematically analysed the expression of SSTR subtype 2 (SSTR2) on inflammatory cells of 33 patients with biopsy- or explant-proven myocarditis (lymphocytic myocarditis (n = 5), giant-cell myocarditis (n = 11), and cardiac sarcoidosis (n = 17)), and in eight controls (multi-organ donors) without signs of myocardial inflammation and/or scars. Results: In all patients, immunohistochemical staining for SSTR2 was positive in areas with CD68-positive macrophages and multinucleated giant cells. Staining for SSTR2 was most prominent in the presence of multinucleated giant cells. The colocalization of both SSTR2 and CD68 on the same cell could be confirmed using immunofluorescence microscopy. Western blotting confirmed the upregulated expression of SSTR2 in cases of granulomatous inflammation (sarcoidosis) of the skeletal and heart muscle, in comparison with controls. Conclusions: In conclusion, our findings demonstrate the expression of SSTR2 on the protein level on CD68-positive macrophages and multinucleated giant cells in various forms of myocarditis, which provides a clear rationale for the diagnostic use of SSTR imaging in this patient group. Full article

Undifferentiated pleomorphic sarcoma (UPS) is an aggressive soft tissue sarcoma with a poor prognosis. The patients are usually found to have metastasis when the primary tumor is diagnosed. Eccrine syringofibroadenoma (ESFA) is a rare cutaneous adnexal lesion of eccrine duct origin. There are five subtypes, one of which is reactive ESFA, known to occur in reaction to an inflammatory or neoplastic process. In this article, we report a case of the co-existence of both UPS and ESFA in a 70-year-old male patient, presenting with a painless, erythematous, irregular surface nodule with a peripherally extended brownish hyperkeratotic plaque on the right palm. The histologic findings revealed an ill-defined dermal tumor of atypical epithelioid and spindle-shaped cells with large pleomorphic hyperchromatic nuclei and abundant eosinophilic cytoplasm. Some of those cells were multinucleated giant cells in the stroma with vascular proliferation and mixed inflammatory cell infiltrate. The tumor cells, which were only positive for vimentin, supported the diagnosis of undifferentiated pleomorphic sarcoma (UPS). Meanwhile, the overlying epidermis demonstrated hyperkeratosis, papillated epidermal hyperplasia, and proliferation of anastomosing slender cords and strands of cuboid cells within loose fibrovascular stroma. These findings are the characteristics of eccrine syringofibroadenoma (ESFA). We describe here a patient in whom reactive ESFA occurred on and surrounded the UPS tumor. Full article

Atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT) is a rare and recently described adipocytic neoplasm that primarily occurs in the subcutis of the limbs and limb girdles, particularly of middle-aged adults. It has locally recurrent potential if incompletely excised but no risk for distant metastasis. ASCPLT is histologically similar to spindle cell/pleomorphic lipoma and atypical lipomatous tumor and shows a mixture of atypical spindle cells, adipocytes, lipoblasts, floret-like multinucleated giant cells, and/or pleomorphic cells. It has been recently recognized that ASCPLT can undergo sarcomatous transformation. However, the biological significance of morphological sarcomatous transformation in ASCPLT remains uncertain. Immunohistochemically, the tumor cells show variable expression of CD34, S-100 protein, and desmin. Loss of nuclear Rb expression is observed in the majority of cases. ASCPLT lacks MDM2 gene amplification but can show RB1 gene deletion in a significant subset of cases. Complete surgical excision is the treatment of choice. This review provides an overview of the current knowledge on the clinicoradiological features, pathogenesis, histopathology, and treatment of ASCPLT. In addition, we will discuss the differential diagnosis of this new entity. Full article

The mononuclear phagocyte system includes monocytes, macrophages, some dendritic cells, and multinuclear giant cells. These cell populations display marked heterogeneity depending on their differentiation from embryonic and bone marrow hematopoietic progenitors, tissue location, and activation. They contribute to tissue homeostasis by interacting with local and systemic immune and non-immune cells through trophic, clearance, and cytocidal functions. During evolution, they contributed to the innate host defense before effector mechanisms of specific adaptive immunity emerged. Mouse macrophages appear at mid-gestation and are distributed throughout the embryo to facilitate organogenesis and clear cells undergoing programmed cell death. Yolk sac, AGM, and fetal liver-derived tissue-resident macrophages persist throughout postnatal and adult life, supplemented by bone marrow-derived blood monocytes, as required after injury and infection. Nobel awards to Elie Metchnikoff and Paul Ehrlich in 1908 drew attention to cellular phagocytic and humoral immunity, respectively. In 2011, prizes were awarded to Jules Hoffmann and Bruce Beutler for contributions to innate immunity and to Ralph Steinman for the discovery of dendritic cells and their role in antigen presentation to T lymphocytes. We trace milestones in the history of mononuclear phagocyte research from the perspective of Nobel awards bearing directly and indirectly on their role in cellular immunity. Full article

A 3-year-old male scarlet macaw parrot (Ara macao) was presented to the Exotic Animal Clinic at the Faculty of Veterinary Medicine, Iași University of Life Sciences (Iași, Romania) for its postmortem examination. According to the owner, the parrot had been raised only in captivity and after 5 days of inappetence, lethargy, and mild respiratory clinical signs, the parrot died. The post mortem examination revealed various-sized granulomas and caseous plaques in the lungs, air sacs, spleen, intestinal serosa, and liver. Microscopically, the granulomas were characterized by a necrotic center and the infiltration of numerous multinucleated giant cells and epithelioid-like cells and by the presence of hyphae typical of Aspergillus spp. Moreover, in the liver tissue, a diffuse inflammation, with numerous fungal hyphae, was noted. The fungal culture and the PCR assay allowed for the isolation and identification of Aspergillus fumigatus from the lung and liver samples. The macroscopical lesions and the histopathological findings, with the fungal isolation and molecular confirmation of Aspergillus fumigatus by nested PCR, provided the basis for the diagnosis of disseminated aspergillosis. To the authors’ best knowledge, this is the first report of disseminated infection caused by Aspergillus fumigatus in a scarlet macaw parrot (Ara macao). Full article