Case report: granulomatous hepatitis due to Mycobacterium avium in an Atlantic yellow-nosed albatross (Thalassarche chlororhynchos) from Southern Brazilian coast.

This study reports a granulomatous hepatitis caused by Mycobacterium avium in an Atlantic yellow-nosed albatross (Thalassarche chlororhynchos) found dead on Brazil southern coast. At necropsy, the albatross was cachectic and the liver was severely enlarged with multifocal to coalescing white nodules. Histopathological evaluation revealed multifocal to coalescing granulomas with caseous necrosis, surrounded by an infiltrate of macrophages and multinucleated giant cells, and a thin capsule of fibrous connective tissue. The Fite-Faraco staining technique revealed multiple acid-fast bacilli (AFB) stained in magenta, predominantly in the areas of necrosis. Bacterial culture and polymerase chain reaction (PCR) analysis confirmed the presence of Mycobacterium avium in liver samples. This case underscores the importance of wildlife surveillance in coastal regions. Pelagic birds like the Atlantic yellow-nosed albatross can harbor pathogenic agents that represent a threat to wildlife and domestic animals. Enhanced monitoring and research are essential to understand the epidemiology and potential risks associated with such infections in coastal ecosystems.

Endogenous PGD2 acting on DP2 receptor counter regulates Schistosoma mansoni infection-driven hepatic granulomatous fibrosis.

Identifying new molecular therapies targeted at the severe hepatic fibrosis associated with the granulomatous immune response to Schistosoma mansoni infection is essential to reduce fibrosis-related morbidity/mortality in schistosomiasis. In vitro cell activation studies suggested the lipid molecule prostaglandin D2 (PGD2) as a potential pro-fibrotic candidate in schistosomal context, although corroboratory in vivo evidence is still lacking. Here, to investigate the role of PGD2 and its cognate receptor DP2 in vivo, impairment of PGD2 synthesis by HQL-79 (an inhibitor of the H-PGD synthase) or DP2 receptor inhibition by CAY10471 (a selective DP2 antagonist) were used against the fibrotic response of hepatic eosinophilic granulomas of S. mansoni infection in mice. Although studies have postulated PGD2 as a fibrogenic molecule, HQL-79 and CAY10471 amplified, rather than attenuated, the fibrotic response within schistosome hepatic granulomas. Both pharmacological strategies increased hepatic deposition of collagen fibers - an unexpected outcome accompanied by further elevation of hepatic levels of the pro-fibrotic cytokines TGF-ß and IL-13 in infected animals. In contrast, infection-induced enhanced LTC4 synthesis in the schistosomal liver was reduced after HQL-79 and CAY10471 treatments, and therefore, inversely correlated with collagen production in granulomatous livers. Like PGD2-directed maneuvers, antagonism of cysteinyl leukotriene receptors CysLT1 by MK571 also promoted enhancement of TGF-ß and IL-13, indicating a key down-regulatory role for endogenous LTC4 in schistosomiasis-induced liver fibrosis. An ample body of data supports the role of S. mansoni-driven DP2-mediated activation of eosinophils as the source of LTC4 during infection, including: (i) HQL-79 and CAY10471 impaired systemic eosinophilia, drastically decreasing eosinophils within peritoneum and hepatic granulomas of infected animals in parallel to a reduction in cysteinyl leukotrienes levels; (ii) peritoneal eosinophils were identified as the only cells producing LTC4 in PGD2-mediated S. mansoni-induced infection; (iii) the magnitude of hepatic granulomatous eosinophilia positively correlates with S. mansoni-elicited hepatic content of cysteinyl leukotrienes, and (iv) isolated eosinophils from S. mansoni-induced hepatic granuloma synthesize LTC4 in vitro in a PGD2/DP2 dependent manner. So, our findings uncover that granulomatous stellate cells-derived PGD2 by activating DP2 receptors on eosinophils does stimulate production of anti-fibrogenic cysLTs, which endogenously down-regulates the hepatic fibrogenic process of S. mansoni granulomatous reaction - an in vivo protective function which demands caution in the future therapeutic attempts in targeting PGD2/DP2 in schistosomiasis.

Granulomatous Panniculitis as an Initial Manifestation of Sjögren Syndrome.

ABSTRACT: A 65-year-old woman presented with unexplained weight loss, recurrent fever, and a dermatosis with painful nodules on the extremities. Biopsies showed focal lobular panniculitis with neutrophilic microgranulomas. Comprehensive investigations ruled out infection and hematologic and solid organ neoplasms. Laboratory results showed anti-Ro/SSA and anti-La/SSB antibody positivity, and elevated inflammatory markers. Dry mouth and eye were confirmed. The diagnosis of Sjögren syndrome with cutaneous panniculitis was established. Prednisone treatment with 30 mg/d resulted in remission of fever and pain improvement. This case emphasizes Sjögren syndrome as an autoimmune disease with multiple cutaneous manifestations and highlights its association with granulomatous panniculitis.

Granulomatous meningoencephalitis and blindness associated with Mycobacterium tuberculosis complex infection in a senile female chimpanzee (Pan troglodytes).

A 40-year old female chimpanzee (Pan troglodytes) developed hyporexia, weight loss, followed by progressive and complete blindness. Tomography demonstrated an intracranial mass in the rostroventral brain involving the optic chiasm, with a presumptive diagnosis of neoplasm. However, histopathology revealed a granulomatous meningoencephalitis, and tissue samples tested positive for Mycobacterium tuberculosis.

Immunohistochemistry and real-time Polymerase Chain Reaction: importance in the diagnosis of intestinal tuberculosis in a Peruvian population.

INTRODUCTION: The diagnosis of intestinal tuberculosis is challenging even nowadays. This study aims to report the positivity rates of new diagnostic methods such as immunohistochemistry and Real-Time Polymerase Chain Reaction in patients with intestinal tuberculosis, as well as describe the pathological and endoscopic features of intestinal tuberculosis in our population. METHODS: This was a retrospective observational study conducted in patients diagnosed with intestinal tuberculosis, between 2010 to 2023 from the Hospital Nacional Daniel Alcides Carrion and a Private Pathology Center, both located in Peru. Clinical data was obtained, histologic features were independently re-evaluated by three pathologists; and immunohistochemistry and real-time Polymerase Chain Reaction evaluation were performed. The 33 patients with intestinal tuberculosis who fulfilled the inclusion criteria were recruited. RESULTS: Immunohistochemistry was positive in 90.9% of cases, while real-time Polymerase Chain Reaction was positive in 38.7%. The ileocecal region was the most affected area (33.3%), and the most frequent endoscopic appearance was an ulcer (63.6%). Most of the granulomas were composed solely of epithelioid histiocytes (75.8%). Crypt architectural disarray was the second most frequent histologic finding (78.8%) after granulomas, but most of them were mild. CONCLUSION: Since immunohistochemistry does not require an intact cell wall, it demonstrates higher sensitivity compared to Ziehl-Neelsen staining. Therefore, it could be helpful for the diagnosis of paucibacillary tuberculosis.

Traumatic Ulcerative Granuloma with Stromal Eosinophilia on the Tongue.

BACKGROUND: Traumatic Ulcerative Granuloma with Stromal Eosinophilia, commonly known as Eosinophilic Ulcer, is a reactive solitary and self-limiting benign lesion. It manifests as a punched-out ulcer with a distinct surrounding indurated border, often raising concerns about malignancy. METHODS: A 44-year-old male presented with a painless, indurated tongue ulcer evolving over three months. Despite being asymptomatic, the patient underwent an incisional biopsy due to suspicions of oral squamous cell carcinoma. RESULTS: Histological analysis revealed a disrupted epithelial lining, dense necrotic connective tissue, and a fibrino-purulent pseudomembrane. Proximal to the ulcer, a collar-like projection of reactive epithelial tissue hyperplasia was noted, accompanied by mononuclear cells and a predominantly histiocytic infiltrate in the submucosal layer surrounding skeletal muscle fibers. The final diagnosis was Traumatic Ulcerative Granuloma with Stromal Eosinophilia. Remarkably, the lesion spontaneously healed within 2 weeks post-biopsy, with no recurrence over 6 months. CONCLUSION: This case emphasizes considering this benign condition in the differential diagnosis of oral ulcers, highlighting the importance of accurate histopathological evaluation to rule out cancer.

Correlation Between Proinflammatory Cytokine Expression and Clinical Data in Apical Granuloma.

INTRODUCTION: This study was intended to evaluate the expression of inflammatory cytokines commonly secreted by CD4+ T cells (IL-2, IL-5, IL-17, TGF-ß, TNF-α, and IFN-γ) in apical granulomas and correlate with the clinical conditions and time elapsed since root canal treatment. METHODS: Eighteen biopsy specimens obtained by periradicular surgery of teeth with post-treatment apical periodontitis and diagnosed as apical granuloma were available from the oral pathology laboratory. Silanized slides containing paraffin sections were used for immunohistochemical reactions. Images were analyzed by using an optical microscopy and each slide was subdivided into 5 fields at high magnification. RESULTS: IFN-γ and TGF-ß were the cytokines with the highest expression levels. There were statistically significant differences when comparing IL-2 and IFN-γ (P < .05), and IL-2 and TGF-ß (P < .05). Comparison between the detected cytokines and clinical data and time of treatment demonstrated significant correlation (P < .05) between lower expression of IL-2 and the presence of painful symptoms, absence of sinus tract, and treatments performed more than 4 years before. It was also possible to observe a significant correlation between lower expression of IL-5 and treatments performed less than 4 years before (P < .05). CONCLUSION: IFN-γ and TGF-ß were highly expressed in apical granulomas. However, only IL-2 and IL-5 levels were associated with clinical data and time since previous root canal treatment.

Intrasellar xanthogranuloma mimicking macroadenoma.

Intracranial xanthogranulomas (XGs) have been found at various sites, but xanthogranuloma of the sellar region is extremely rare. We report about a case of sellar XG in a 34-year-old female. Magnetic resonance imaging showed a solid-cystic mass located at the sella turcica. The cystic component was hyperintense on the T1-weighted image (WI) and T2WI. The solid component was hyperintense on T1WI and hypointense on T2WI. There was peripheral enhancement after gadolinium administration. The diagnosis of cystic macroadenoma was considered before surgery. Final diagnosis of XG was confirmed by histopathological examination after surgical resection. Gross total resection of the lesion was achieved using the microscope through endoscopic endonasal transsphenoidal approach. The patient had a good outcome and no symptom of diabetes insipidus, hormonal evaluation did not show any alterations compatible with hypopituitarism and prolactin levels were normal XG should receive diagnostic consideration for the sellar mass lesions with cystic components hyperintense on T1WI and T2WI, solid components hyperintense on T1WI and hypointense on T2WI, and CT without evidence of calcifications. It is important to consider the possibility of XG when pertinent, as it facilitates a proper surgical approach strategy.

The contribution of histopathology to the diagnosis of tuberculosis. Lessons from archival biopsy samples / La contribución de la histopatología al diagnóstico de la tuberculosis. Lecciones de muestras de biopsias de archivo

BACKGROUND: Histopathological analysis of tissue samples is an ancillary complementary diagnostic tool in tuberculosis (TB) with variable sensitivity and specificity according to different clinical settings. We evaluated the spectrum of histological findings, their diagnostic sensitivity, diagnostic utility, and requests over time in a sample of archival biopsies. METHODS: Analysis of biopsies of confirmed TB cases between years 2011-2019 at a reference hospital in Chile. RESULTS: The series included patients with a histological study for TB confirmed by culture (88.9%) or PCR (11.1%). In total, 34 samples were available for analysis, most of them of extrapulmonary origin (82.4%). Biopsies were taken before the start of treatment in 26 cases (76.5%) or after the start-end of treatment for different reasons in 8 cases (23.5%). Restricting the analysis to the group with pretreatment biopsies, the prevalence/diagnostic sensitivity of granulomas was 93.3%, 69.2% for caseous necrosis, 26.9% for granulomas with caseous necrosis without acid-fast bacilli (AFB), and 46.2% for AFB in any histological context. A histological score was constructed to evaluate the homogeneity of lesions, observing that 76.9% had at least four of the six components of the score. The request for biopsies was maintained over time despite the increase in the use of molecular techniques. The presence of AFB contributed to the diagnosis before microbiological results in 23.1% of the cases. Conclusions: Histological study continues to contribute to the diagnosis of TB, especially in extrapulmonary forms.

El análisis histopatológico de muestras de tejidos es una metodología antigua y auxiliar para el diagnóstico de tuberculosis (TB) con sensibilidad y especificidad variable de acuerdo al escenario clínico. Evaluamos el espectro de los hallazgos histológicos, su sensibilidad diagnóstica, su utilidad diagnóstica y cambios de solicitud en el tiempo. MÉTODOS: Análisis de biopsias de casos de TB confirmados entre los años 2011-2019 en un hospital de referencia en Chile. RESULTADOS: La serie incluye pacientes con estudio histológico por TB confirmados por cultivo (88,9%) o PCR (11,1%). En total se contó con 34 muestras para análisis, en su mayoría de origen extrapulmonar (82,4%). Las biopsias fueron tomadas antes del inicio del tratamiento en 26 casos (76,5%) o luego del inicio o al finalizar el tratamiento por diferentes razones en 8 casos (23,5%). Restringiendo el análisis al grupo con biopsias pretratamiento, la prevalencia/sensibilidad diagnóstica de granulomas fue de 93,3%, de necrosis caseosa 69,2%, de granulomas con necrosis caseosa sin bacilos ácido-alcohol resistentes (BAAR) de 26,9% y de BAAR en cualquier contexto histológico de 46,2%. Se construyó un score histológico para ver homogeneidad de lesiones, observando que el 76,9% tenía al menos 4 de los 6 componentes del score. La solicitud de biopsias se mantuvo en el tiempo a pesar del incremento de técnicas moleculares. La presencia de BAAR contribuyó al diagnóstico antes que los resultados microbiológicos en el 23,1% de los casos. Conclusiones: El estudio histológico sigue contribuyendo al diagnóstico, especialmente en las formas extrapulmonares de TB.

Role of the IL-33/ST2 Activation Pathway in the Development of the Hepatic Fibrosis Induced by Schistosoma mansoni Granulomas in Mice.

Schistosoma mansoni eggs retained in host tissues induce innate cytokine release, contributing to the induction of Type-2 immune responses and granuloma formation, important to restrain cytotoxic antigens, but leading to fibrosis. Interleukin(IL)-33 participates in experimental models of inflammation and chemically induced fibrosis, but its role in S. mansoni-induced fibrosis is still unknown. To explore the role of the IL-33/suppressor of the tumorigenicity 2 (ST2) pathway, serum and liver cytokine levels, liver histopathology, and collagen deposition were comparatively evaluated in S. mansoni-infected wild-type (WT) and IL-33-receptor knockout (ST2-/-) BALB/c mice. Our data show similar egg counts and hydroxyproline in the livers of infected WT and ST2-/- mice; however, the extracellular matrix in ST2-/- granulomas was loose and disorganised. Pro-fibrotic cytokines, such as IL-13 and IL-17, and the tissue-repairing IL-22 were significantly lower in ST2-/- mice, especially in chronic schistosomiasis. ST2-/- mice also showed decreased α-smooth muscle actin (α-SMA) expression in granuloma cells, in addition to reduced Col III and Col VI mRNA levels and reticular fibres. Therefore, IL-33/ST2 signalling is essential for tissue repairing and myofibroblast activation during S. mansoni infection. Its disruption results in inappropriate granuloma organisation, partly due to the reduced type III and VI collagen and reticular fibre formation.

Fish tank granuloma not associated to Mycobacterium marinum but to Microbacterium paraoxydans.

Fish tank granuloma has traditionally been associated with Mycobacterium marinum. We report the case of a 54 old-year woman that worked in a freshwater fish pet store and developed a skin ulcer in a hand finger with a suppurative granuloma secondary to Microbacterium paraoxydans. This is a bacterial fish pathogen, rarely observed in human infections. Identification was performed by colony morphology and MALDI-TOF. She evolved satisfactorily after receiving a sequential treatment with beta-lactams and linezolid. To our knowledge, it is the first known description of this type.

The contribution of histopathology to the diagnosis of tuberculosis. Lessons from archival biopsy samples.

BACKGROUND: Histopathological analysis of tissue samples is an ancillary complementary diagnostic tool in tuberculosis (TB) with variable sensitivity and specificity according to different clinical settings. We evaluated the spectrum of histological findings, their diagnostic sensitivity, diagnostic utility, and requests over time in a sample of archival biopsies. METHODS: Analysis of biopsies of confirmed TB cases between years 2011-2019 at a reference hospital in Chile. RESULTS: The series included patients with a histological study for TB confirmed by culture (88.9%) or PCR (11.1%). In total, 34 samples were available for analysis, most of them of extrapulmonary origin (82.4%). Biopsies were taken before the start of treatment in 26 cases (76.5%) or after the start-end of treatment for different reasons in 8 cases (23.5%). Restricting the analysis to the group with pretreatment biopsies, the prevalence/diagnostic sensitivity of granulomas was 93.3%, 69.2% for caseous necrosis, 26.9% for granulomas with caseous necrosis without acid-fast bacilli (AFB), and 46.2% for AFB in any histological context. A histological score was constructed to evaluate the homogeneity of lesions, observing that 76.9% had at least four of the six components of the score. The request for biopsies was maintained over time despite the increase in the use of molecular techniques. The presence of AFB contributed to the diagnosis before microbiological results in 23.1% of the cases. CONCLUSIONS: Histological study continues to contribute to the diagnosis of TB, especially in extrapulmonary forms.

Pulmonary Granuloma Is Not Always the Tuberculosis Hallmark: Pathology of Tuberculosis Stages in New World and Old World Monkeys Naturally Infected with the Mycobacterium tuberculosis Complex.

We present the pathology of monkeys naturally infected with Mycobacterium tuberculosis complex from five different colonies in Rio de Janeiro, Brazil. On the basis of gross and histopathological findings, the lesions were classified into chronic-active, extrapulmonary, early-activation or latent-reactivation stages. Typical granulomatous pneumonia was seen in 46.6% of cases (six rhesus monkeys [Macaca mulatta] and one Uta Hick's bearded saki [Chiropotes utahickae]). The absence of pulmonary granulomas did not preclude a diagnosis of tuberculosis (TB): classical granulomatous pneumonia was observed in the chronic-active and latent-reactivation stages but not in the extrapulmonary and early-activation stages. The early-activation stage was characterized by interstitial pneumonia with a predominance of foamy macrophages and molecular and immunohistochemical evidence of M. tuberculosis complex infection. TB should be considered as a cause of interstitial pneumonia in New World Monkeys. We recommend the use of immunohistochemistry and molecular analysis for diagnosis of TB, even when typical macroscopic or histological changes are not observed.

The hepatic extramedullary hematopoiesis during experimental murine Schistosomiasis mansoni.

Many years ago, our research group has demonstrated extramedullary hematopoiesis in the peripheral zone of murine hepatic schistosomal granulomas. In the present study, we revisit this phenomenon using new technical and conceptual approaches. Therefore, newborn mice were percutaneously infected by Schistosoma mansoni cercariae and euthanized between 35- and 60-days post infection. Liver samples were submitted to histopathology and immunohistochemical analyses. Cells under mitosis and/or expressing Ki67 demonstrated the proliferation of hematopoietic cells both around the parasite's eggs trapped in the liver and around hepatic vessels. After 50 days post infection, proliferating cells at different levels on differentiation were located preferentially in the peripheral zone of the granulomas, around the vessels and inside the sinusoids. The presence of acidic and sulfated glycoconjugates, reticular fibers and the absence of fibronectin characterized the microenvironment for attraction and maintenance of hematopoiesis. Some neutrophils secreted MMP9 from the earliest points of infection, indicating degradation of the extracellular matrix in regions of histolysis and a possible chemoattraction of hematopoietic stem cells to the liver. Fall-3+ cells and Sca-1+ cells indicated that early hematopoietic progenitors could be mobilized to the liver. Groups of vWF+ megakaryocytes suggest chemoattraction of these cells and/or migration, proliferation, and differentiation of very immature progenitors to this organ. The increase of blood vessels and extramedullary hematopoiesis in this environment, where markers of immature hematopoietic and endothelial cells have been identified, points to the possibility of the presence of progenitors for endothelial and hematopoietic cells in the liver during the infection. There is also the possibility of concomitant migration of more differentiated hematopoietic progenitors, that proliferate and differentiate in the liver, and the occurrence of angiogenesis caused by inflammation or release of ovular antigens that stimulate the activation and proliferation of endothelial cells. Altogether, these data increase knowledge about a murine model that is of interest for investigating the pathology of the schistosomiasis and also the dynamics of hematopoiesis.

Alternate-day fasting, a high-sucrose/caloric diet and praziquantel treatment influence biochemical and behavioral parameters during Schistosoma mansoni infection in male BALB/c mice.

Schistosoma mansoni-induced granulomas result in severe damage to the host's liver, as well as neurological and metabolic disorders. We evaluated the biochemical and behavioral changes during schistosomiasis under three diet protocols: ad libitum (AL), alternate-day fasting (ADF) and a high-sucrose/caloric diet (HSD). Healthy male BALB/c mice were divided into noninfected, matched infected and infected/treated [praziquantel (PZQ)] groups. Caloric intake and energy efficiency coefficients associated with diets were measured. Behavioral (exploratory and locomotor) and biochemical (glucose, triglycerides, total cholesterol, AST, ALT, ALP, and γ-GT) tests and histological analysis were performed. Fifteen weeks postinfection, HSD and PZQ promoted weight gain, with higher caloric consumption than ADF (p < 0.05), reflecting serum glucose levels and lipid profiles. HSD and PZQ prevented liver dysfunction (AST and ALT) and significantly prevented increases in granuloma area (p < 0.05). HSD and PZQ also significantly improved mouse physical performance in exploratory and locomotor behavior (p < 0.05), reversing the impaired motivation caused by infection. These findings showed that ADF worsened the course of S. mansoni infection, while HSD and PZQ, even with synergistic effects, prevented and/or attenuated biochemical and behavioral impairment from infection.

Canine Leproid Granuloma (CLG) Caused by Mycobacterial Species Closely Related to Members of Mycobacterium Simiae Complex in a Dog in Brazil.

This report describes the clinical features and molecular diagnosis of a case of canine leproid granuloma (CLG) caused by mycobacterial strains of the Mycobacterium simiae complex in Brazil. A 12-year-old non-neutered male Labrador Retriever dog was presented with a 2-week history of progressive painless cutaneous lesions. Ulcerated nodules with hematic crusts were observed on the dorsal surface of the right and left pinna and on the metacarpal, metatarsal, and digits. Complete blood count, serum biochemistry, aspiration cytology of cutaneous lesions, biopsy for histopathological evaluation, culture for aerobic and anaerobic bacteria, polymerase chain reaction and DNA sequencing to identify mycobacterial species were performed. According to the clinical and histopathological findings, a diagnosis of CLG was established. Despite the negative result of the bacterial culture, mycobacterial identification was made by sequencing the hsp65 gene. Our findings highlight that mycobacterial species closely related to members of the M simiae clade can be causative agents of CLG.

Orbitopalpebral and ocular sarcoidosis: what does the ophthalmologist need to know.

Sarcoidosis is a chronic multisystemic disease of unknown aetiology, characterised by non-caseating granulomas. Ocular involvement rate ranges from 30% to 60% among individuals with sarcoidosis, and can vary widely, making the diagnosis a challenge to the ophthalmologist. Cutaneous manifestations occur in about 22% of sarcoidosis cases, but eyelid involvement is rare. Eyelid swelling and nodules are the most frequent forms of eyelid involvement, but other findings have been reported. The joint analysis of clinical history, ancillary exams and compatible biopsy is needed for the diagnosis, as well as the exclusion of other possible conditions. This review aims to describe the different forms of presentations, the clinical reasoning and treatment options for ocular, eyelid and orbital sarcoidosis.

Histopathologic Spectrum of Findings Associated With Tattoos: Multicenter Study Series of 230 Cases.

IMPORTANCE: Reactions to tattoo may simulate common dermatosis or skin neoplasms. Histopathology allows diagnosis and helps determining the level and degree of inflammation associated, consequently orientating treatment. OBJECTIVE: To describe the histological features found in biopsies of cutaneous reactions to tattoo. DESIGN: This study was designed as a multicenter case series. SETTING: All consecutive histopathological samples of tattoos referred from 1992 to 2019 to the Hospital General de Catalunya, Hospital Germans Trias i Pujol, and a private practice, all in Barcelona, Spain, and from the Kempf und Pfaltz Histologische Diagnostik in Zurich, Switzerland were retrieved from the files. PARTICIPANTS AND EXPOSURE: The inclusion criteria were all cosmetic/permanent makeup, artistic/professional, and traumatic tattoos associated with either inflammatory reactions alone and/or with tumors and/or infections. Exclusion criteria were cases without any associated pathologic finding in the place of the ink, amalgam tattoos, and medical or temporary tattoos. MAIN OUTCOMES AND MEASURES: In all patients, clinical features (age, sex, location, tattoo color, and presentation) were recorded. Histological features evaluated included ink color, associated tumors or infections, and inflammatory reaction pattern. Inflammation was graded in low to moderate or severe. RESULTS: From 477 biopsies diagnosed as tattoos, 230 cases from 226 patients met the inclusion criteria. Samples corresponded to 107 male and 120 female subjects and 3 of unknown gender. Median age was 39 years (ranging from 9 to 84 years). Fifty-three samples were referred from centers in Spain and 177 from the center in Switzerland. The series was analyzed in 2 parts: tattoos associated only with inflammatory reactions (117/230) and tattoos associated with tumors or infections (113/230). The most common form of inflammatory pattern associated with tattoo was the fibrosing reaction (79/117, 68%), followed by granulomatous reaction (56/117, 48%), lichenoid reaction (33/117, 28%), epithelial hyperplasia (28/117, 24%), pseudolymphoma (27/117, 23%) and spongiotic reaction (27/117, 23%). Combined features of 2 or more types of inflammatory patterns were seen in 64% cases. CONCLUSIONS AND RELEVANCE: Our series confirms that cutaneous reactions to tattoos are polymorphous. Inflammation tends to present with combined patterns. Infections are tending to decline, and pathologic findings are not specific to ink color or clinical features.