Granulomas en dermatopatología: principales entidades. Parte I / Granulomas in Dermatopathology: Principal Diagnoses - Part 1

En esta serie de 2 artículos realizamos una revisión de las principales entidades dermatopatológicas que cursan con granulomas. Esta primera parte se ha centrado en la aclaración de los conceptos, la presentación de los tipos de granulomas y de las células gigantes, así como en entidades muy diversas de origen no infeccioso. Algunas de ellas de origen metabólico, como la necrobiosis lipoídica: otras relacionadas con linfomas, como la micosis fungoides granulomatosa, y otras tan extendidas que casi resultan un problema cotidiano en las consultas de dermatología, como la rosácea (AU)

This series of 2 articles on dermatopathologic diagnoses reviews conditions in which granulomas form. Part 1 clarifies concepts, discusses the presentation of different types of granulomas and giant cells, and considers a large variety of noninfectious diseases. Some granulomatous diseases have a metabolic origin, as in necrobiosis lipoidica. Others, such as granulomatous mycosis fungoides, are related to lymphomas. Still others, such as rosacea, are so common that dermatologists see them nearly daily in clinical practice (AU)

Granulomas en dermatopatología: principales entidades. Parte II / Granulomas in Dermatopathology: Principal Diagnoses — Part 2

Esta es la segunda parte de una serie dedicada a la patología granulomatosa en la biopsia cutánea. Mientras que en la primera parte hablamos, entre otras, de algunas condiciones metabólicas y tumorales, esta segunda parte abordará fundamentalmente patología infecciosa de diversos tipos, junto con otras condiciones relativamente frecuentes en las consultas de dermatología (AU)

Part 2 of this series on granulomatous diseases focuses on skin biopsy findings. Whereas the first part treated noninfectious conditions (metabolic disorders and tumors, among other conditions), this part mainly deals with various types of infectious disease along with other conditions seen fairly often by clinical dermatologists (AU)

Immunohistochemical expression of interferon-γ in different types of granulomatous lesions associated with bovine paratuberculosis.

Animals infected with Mycobacterium avium subsp. paratuberculosis (Map) show a variety of lesions, from focal forms, seen in subclinical stages to diffuse lesions in clinical cases. The purpose of this study was to evaluate the local expression of IFN-γ by immunohistochemistry in relation with the type of lesion in naturally Map-infected cows. The number of immunolabelled cells, -the majority morphologically consistent with lymphocytes-, was higher in focal and diffuse paucibacillary forms than in diffuse multibacillary lesions, where they appeared closely related to epithelioid cells. Diffuse multibacillary lesions had the lowest numbers, but higher than controls, and positive cells were intermingled among the macrophages. The peripheral IFN-γ production was higher in all Map infected cows and a positive correlation was found with the number of immunolabelled cells in the intestine. The findings of this study show that IFN-γ would play a role in the development of the different types of lesions in paratuberculosis, and also points out the importance of adequate sampling of lymphoid tissue containing samples when studying the local immune response in which IFN-γ expression may be involved, especially in cases where focal lesions are present.

Disseminated hyaline ring granuloma in the omentum of a dog.

BACKGROUND: Hyaline ring granuloma (HRG) is an uncommon histopathologic finding of unsolved etiopathogenesis. According to the exogenous theory, HRG develops due to implantation of foreign material, most probably indigestible plant fragments. HRG is a comparatively rare condition in humans, mostly involving the oral cavity with very rare extraoral locations. CASE PRESENTATION: An 1-year-old mixed-breed dog in good condition was presented for routine ovariohysterectomy. Disseminated HGR were accidentally found in the omental adipose tissue during surgery. Histopathology revealed the presence of ring-like hyaline structures surrounded by granulomatous inflammation including foreign body-type multinucleated giant cells. The histochemical examinations indicated the exogenous plant origin of the foreign material. CONCLUSIONS: The lesions were similar to the findings in humans with HRG. The definitive diagnosis remains largely based on histopathological examination supported by special histochemical stains. To the best of our knowledge, this is the first case of hyaline ring granuloma reported in a non-human species. Moreover, the omentum is an uncommon location for this condition.

IFN-gamma role in granuloma formation in experimental subcutaneous cysticercosis.

Cysticercosis is an infection caused by the metacestode larval stage of Taenia parasites in tissues and elicits a host-parasite reaction in which the immune response may be decisive in the disease development. The aim of this study was to evaluate the role of IFNγ (IFN-gamma) in the experimental model of subcutaneous infection with Taenia crassiceps (T. crassiceps) cysticerci using IFNγ knockout mice. Male C57BL/6 and C57BL/6 KO IFNγ mice 8-12 weeks of age were inoculated with T. crassiceps cysticerci into the subcutaneous tissue of the dorsum. At 7 and 30 (acute phase), 60 and 90 (chronic phase) days post infection, animals from each group had their blood and the subcutaneous tissues collected for serologic and pathological studies. IFNγ and IL-4 were dosed and the histopathological analysis was performed. In the presence of IFNγ there was the establishment of a mixed Th1/Th2 systemic immune profile. This profile also locally induced the granuloma formation which was constituted by cells that played important roles in the parasitary destruction and that were likely associated to the Th1 axis of mixed immune response. On the other hand, the absence of IFNγ appears to favor the parasitary growth which may be related to the development of a systemic Th2 immune response. This profile influenced the granuloma formation with immunoregulatory properties and appears to be important in the collagen synthesis.

Diagnóstico diferencial de tuberculosis en base a PCR en lesiones granulomatosas clasificadas histopatológicamente / PCR-based differential diagnosis of tuberculosis in histopathologically classified granulomatous lesions

El diagnóstico diferencial de tuberculosis en tejidos fijados en formalina e incluidos en parafina es necesario porque la morfología de la lesión tuberculosa es variada, hay diversos granulomas clasificados en necrobióticos, tuberculoideos, supurativos, sarcoideo, a cuerpo extraño/crónico inespecífico. Las lesiones granulomatosas ocurren en tuberculosis y también en otras infecciones (hongos, parásitos, brucelosis, lepra) en condiciones tóxicas, alérgicas, autoinmunes, tumores y otras. El diagnóstico histológico no es confirmatorio de tuberculosis y en ausencia de una baciloscopia positiva, se hace necesaria la confirmación molecular para el diagnóstico diferencial. Evaluamos la eficacia de la técnica de PCR para la detección de tuberculosis en tejidos fijados y comparamos esos resultados con la histología del granuloma y la baciloscopia. Analizamos 444 biopsias de diferentes tejidos (ganglios, piel, pleura, pulmón, intestino, tejido óseo, mama y otros) de 5 tipos de granulomas: G1.tuberculoideo con necrosis caseosa; G2.tuberculoideo sin necrosis caseosa; G3. supurativo; G4. sarcoideo l; G5. a cuerpo extraño/inespecífico. Utilizamos dos PCR-IS6110 nested para detección del complejo Mycobacterium tuberculosis y un pan PCR-hsp65 nested para detección de Mycobacterium spp. Los resultados obtenidos muestran que la detección de tuberculosis mediante PCR fue significativamente superior que mediante baciloscopia. G1: PCR 69,6%, baciloscopia 31,3%; G2: PCR 26,8%, baciloscopia 6,1%; G3: PCR 16,7%, baciloscopia 6,7%; G4: PCR 7%, baciloscopia 4%; G5: PCR 6,7%, baciloscopia 0%. Concluimos que el diagnóstico molecular de tuberculosis mediante un PCR robusto adaptado a tejidos fijados es eficaz, rápido, sensible y contribuye a la precisión del diagnóstico diferencial en diferentes tipos de granulomas (AU)

The differential diagnosis of tuberculosis in fixed paraffin embedded-tissues is necessary due to both the diverse morphology of tuberculous lesions and the varying histological types of granulomas (necrobiotic, tuberculoid, suppurative, sarcoidal and foreign body/inespecific). Granulomatous lesions occur in tuberculosis, in other infections (fungal, parasitic, brucelosis, lepra), in toxic, allergic and autoimmune, tumours and in conditions of unknown etiology. Diagnosis of tuberculosis cannot be confirmed by histopathology alone and in absence of a positive acid-fast bacilli (AFB) stain, molecular confirmation of tuberculosis is necessary for a correct differential diagnosis. The aim of our study was to assess PCR efficacy for mycobacterial infection detection in fixed tissues and to correlate those findings with granuloma histology and with AFB staining. We analyzed 444 biopsies from various tissues (lymph nodes, skin, pleura, lung, intestine, bone tissue, breast and others) with 5 granuloma types: G1: with caseous necrosis; G2: without caseous necrosis; G3: suppurative; G4: sarcoidal; G5: chronic/nonspecific. For molecular detection, we used nested PCR-IS6110 for Mycobacterium tuberculosis complex and a nested pan PCR-hsp65 for Mycobacterium sp.. The results obtained demonstrated that PCR was significantly better than AFB stain for tuberculosis detection. G1: PCR 69.6%, AFB staining 31.3%. G2: PCR 26.8%, AFB staining 6.1%; G3: PCR 16.7%, AFB staining 6.7%; G4: PCR 7%, AFB staining 4%. G5: PCR 6.7%, AFB staining 0%. We conclude that molecular diagnosis of tuberculosis using robust PCR-based testing adapted to fixed tissues is a fast, efficient and sensitive method that increases the accuracy of the differential diagnosis of granulomatous lesions (AU)

Reactive Granulomatous Dermatitis: A Review of Palisaded Neutrophilic and Granulomatous Dermatitis, Interstitial Granulomatous Dermatitis, Interstitial Granulomatous Drug Reaction, and a Proposed Reclassification.

The terms "palisaded neutrophilic and granulomatous dermatitis," "interstitial granulomatous dermatitis," and the subset "interstitial granulomatous drug reaction" are a source of confusion. There exists substantial overlap among the entities with few strict distinguishing features. We review the literature and highlight areas of distinction and overlap, and propose a streamlined diagnostic workup for patients presenting with this cutaneous reaction pattern. Because the systemic disease associations and requisite workup are similar, and the etiopathogenesis is poorly understood but likely similar among these entities, we propose the simplified unifying term "reactive granulomatous dermatitis" to encompass these entities.

The Dacryocystorhinostomy Ostium Granulomas: Classification, Indications for Treatment, Management Modalities and Outcomes.

AIM: Ostium granulomas following dacryocystorhinostomy (DCR) have not been studied in detail previously. This study aims to classify the DCR-related granulomas based on their ostial locations and to assess the outcomes of their management. METHODS: A retrospective consecutive case series of 47 ostial granulomas evaluated over a period of 2 years were included in this study. All patients underwent detailed endoscopic examination to assess the granuloma locations and their response to initial topical steroids treatment. Persistent granulomas either underwent further management with excision or intralesional steroids based on their location. Patients were followed up for a minimum of 6 months. The primary outcome measure was resolution of granuloma. RESULTS: The mean age at presentation was 45 years with a female preponderance (68%). 70% (33/47) of granulomas were following external DCR and 30% (14/47) occurred in the setting of endonasal DCR. The most common location was an edge granuloma in 46.8% (22/47) followed by a combined granuloma in 21.2% (10/47). 91.4% (43/47) underwent initial treatment with topical nasal steroids. The remaining 4 (8.5%) underwent primary excision. Among those treated with topical steroids (n = 43), 9.3% (4/43) underwent further treatment with intralesional triamcinolone. Overall, 4.2% (2/47) recurred in 6 weeks following resolution and were treated with excision. CONCLUSION: We recommend routine endoscopic evaluation of all the DCR ostia. Detection of granulomas in early stages and appropriate management as per guidelines proposed may aid in better outcomes.

Granulomatous inflammation: The overlap of immune deficiency and inflammation.

Pediatric granulomatous diseases constitute a heterogenous group of conditions in terms of clinical phenotypes, pathogenic mechanisms, and outcomes. The common link is the presence of multinucleated giant cells in the inflammatory infiltrate. The clinical scenario in which a tissue biopsy shows granulomatous inflammation is not an uncommon one for practicing adult and pediatric rheumatologists. Our role as rheumatologists is to develop a diagnostic plan based on a rational differential diagnostic exercise tailored to the individual patient and based mainly on a detailed clinical assessment. This chapter presents a comprehensive differential diagnosis associated with a classification developed by the authors. We describe with some detail extrapulmonary sarcoidosis, Blau syndrome, and immunodeficiency associated granulomatous inflammation, which in our view are the paradigmatic primary forms of granulomatous diseases in childhood. The other entities are presented only as differential diagnoses listing their most relevant clinical features. This chapter shows that almost all granulomatous diseases seen in adults can be found in children and that there are some entities that are essentially pediatric at onset, namely Blau syndrome and most forms of immunodeficiency associated granulomatous diseases.

Granulomatous lymphadenitis.

In this review, representative types of granulomatous lymphadenitis (GLA) are described. GLA can be classified as noninfectious GLA and infectious GLA. Noninfectious GLA includes sarcoidosis and sarcoid-like reaction. The cause of sarcoidosis remains unknown, but it has good prognosis. Sarcoid-like reaction, which is considered to be a biological defense mechanism, is observed in regional lymph nodes with many underlying diseases. Infectious GLA can be classified as suppurative lymphadenitis (LA) and nonsuppurative LA. Suppurative LA generally shows follicular hyperplasia and sinus histiocytosis in the early phase. In tularemia and cat scratch disease, monocytoid B lymphocytes (MBLs) with T cells and macrophages contribute to the formation of granuloma. However, none of the epithelioid cell granulomas of Yersinia LA contains MBLs like in cat scratch disease. In addition, almost all have a central abscess in granulomas induced by Gram-negative bacteria. In terms of the lymph nodes, tularemia and cat scratch disease are apt to affect the axillary and cervical regions while Yersinia LA affects the mesenteric lymph node. Nonsuppurative LA includes tuberculosis and BCG-histiocytosis. These are induced by delayed allergic reaction of M. tuberculosis. Tuberculosis LA mainly appears in the cervical lymph node. Organisms are histologically detected by Ziehl-Neelsen staining in the necrotic area. Toxoplasmosis is also a nonsuppurative protozoan infection (Toxoplasma gondii). In toxoplasma LA, MBLs can also be seen, but round and organized, well-formed granulomas are not found in this disease. Furthermore, necrosis is not induced and there are no accompanying neutrophils, eosinophils and fibrosis. GLA described above is associated with characteristic histological findings. An accurate pathological diagnosis using the above findings can lead to precise treatment.

Tecido de granulação e granuloma: dois termos com significados muito diferentes / Granulation tissue and granuloma: two terms with very different meanings

A confusão conceitual e o diagnóstico microscópico equivocado são comuns no emprego dos termos tecido de granulação e granuloma. Quando as áreas lesadas estão livres do agente agressor, o tecido de granulação, um tecido quase embrionário, forma-se no local para dar lugar a um novo tecido conjuntivo, restabelecendo-se a normalidade e/ou preenchendo espaços. Por outro lado, a persistência do agressor promove a continuidade da inflamação com macrófagos e células derivadas circunscrevendo-os, limitando sua agressividade. Esses aglomerados de macrófagos ao redor do persistente agressor recebem o nome de granulomas, um sinônimo de inflamação crônica. Apesar da sonoridade parecida, os termos granuloma e tecido de granulação representam fenômenos distintos e não devem ser utilizados como sinônimos nas análises microscópicas, pois isso induz a interpretações equivocadas.

The conceptual confusion and the mistaken microscopical diagnosis are often when using the terms granulation tissue and granuloma. When the wounded areas are free of the aggressor agent, the granulation tissue, an almost embryonic tissue, is formed on the area to give place to a new conjunctive tissue, reestablishing the normality and/or filling the spaces. On the other hand, the aggressor persistence promotes the inflammation continuation with macrophages and derived cells, limiting its aggressiveness. These macrophages agglomerated around thepersistent aggressor receive the name of granulomas, synonym of chronicle inflammation. Despite of the similar sonority, the terms granuloma and granulation tissue represent different phenomena and must not be used as synonyms in the microscopical analyses because this would lead to mistaken interpretations.

Limitations of clinico-histopathological correlation of skin biopsies in leprosy.

BACKGROUND: Skin biopsies play an important role in diagnosing and classifying different types of leprosy. The aim of this study was to analyse different histologic types of leprosy, to correlate histopathological diagnosis with clinical diagnosis, to study the uniformity of clinical and histological findings in the diagnosis of leprosy and to evaluate difficulties faced during clinicopathological correlation according to Ridley- Jopling classification due to inadequacy of data provided. METHODS: This is a retrospective study of all skin biopsies reported from Department of Pathology of Tribhuvan University Teaching Hospital from 14 April 2007 to 13 April 2009, for which leprosy was the diagnosis or was strongly suspected on histopathology. RESULTS: Out of 40 cases included, 33 were males and seven were females. Tuberculoid leprosy was the most common type comprising 23 /40 cases (57.5%). In 18/ 40 cases (45%), clinical diagnosis was leprosy. Only in three, leprosy was classified according to Ridley-Jopling criteria clinically. Thus clinicopathological correlation according to Ridley-Jopling criteria could not be done. Histopathological reporting lacked uniformity too. In 13/40 reports (32.5%), exact location of granuloma, presence or absence of Grenz zone and enroachment of epidermis by granuloma was not mentioned. None mentioned the number and distribution of lymphocytes or relative proportion of epithelioid cells and foamy histiocytes. Results: Out of 40 cases included, 33 were males and seven were females. Tuberculoid leprosy was the most common type comprising 23 /40 cases (57.5%). In 18/ 40 cases (45%), clinical diagnosis was leprosy. Only in three, leprosy was classified according to Ridley-Jopling criteria clinically. Thus clinicopathological correlation according to Ridley-Jopling criteria could not be done. Histopathological reporting lacked uniformity too. In 13/40 reports (32.5%), exact location of granuloma, presence or absence of Grenz zone and enroachment of epidermis by granuloma was not mentioned. None mentioned the number and distribution of lymphocytes or relative proportion of epithelioid cells and foamy histiocytes. CONCLUSIONS: Histopathological diagnosis of leprosy did not correlated with clinical diagnosis significantly. Uniformity was not seen in the clinical or histopathological informations provided making it difficult to conduct retrospective clinico pathological correlation.

[Myositides]. / Myositiden.

Idiopathic inflammatory myopathies (IIM) are diseases that are potentially amenable to immunomodulatory therapy. The challenge for the neuropathologist consists in distinguishing these myopathies from secondary inflammatory myopathies, especially in the context of some muscular dystrophies and metabolic diseases that may also show inflammatory infiltrates. There are generalized IIMs (dermatomyositis, polymyositis, sporadic inclusion body myositis) and focal ones (e.g., proliferative myositis, macrophagic myofasciitis). This review provides diagnostic criteria for each of these and includes pathogenetic mechanisms where available.

Hepatic granulomas in canine visceral leishmaniasis and clinical status

The histopathological description of intralobular hepatic granulomas in animals with a defined clinical status (asymptomatic, oligosymptomatic and symptomatic animals) was reported. Seventy-one mongrel dogs naturally infected with Leishmania chagasi were obtained from two Brazilian endemic areas: João Pessoa, PB and Belo Horizonte, MG. The hepatic parasite load was determined and compared to granuloma formation. Liver fragments from all infected animals showed remarkable leishmaniotic granulomatous inflammatory reaction. Granulomas with variable size were constituted by macrophages (parasitized or not with amastigotes of L. chagasi), some epithelioid cells, small numbers of lymphocytes, plasma cells, and rare neutrophils. Asymptomatic dogs had higher numbers of granulomas than oligosymptomatic and symptomatic animals from both geographical regions. However, the average diametric size of granulomas was very heterogeneous in all groups, independently of the geographic region (P>0.05). Parasite tissue load did not show any difference among liver fragments of all animals, especially when considering the defined clinical status and/or their geographic origin

Descreve-se a formação de granulomas hepáticos na leishmaniose canina em animais com classificação clínica definida - assintomáticos, oligossintomáticos e sintomáticos. Setenta e um animais, sem raça definida e naturalmente infectados com Leishmania chagasi, foram obtidos de duas regiões endêmicas brasileiras: João Pessoa, PB e Belo Horizonte, MG. A carga parasitária tecidual foi determinada mediante emprego do Leishmania Donovani Units (LDU) e comparada com a formação de granulomas hepáticos. Fragmentos de fígado de todos os animais infectados mostraram reação granulomatosa notadamente leishmaniótica. Granulomas de variáveis tamanhos eram constituídos por macrófagos, parasitados ou não com formas amastigotas de L. chagasi, algumas células epitelióides, pequeno número de linfócitos e plasmócitos, e raros neutrófilos. Cães assintomáticos apresentaram maior número de granulomas do que os animais oligossintomáticos e sintomáticos, em ambas as regiões geográficas. As médias dos diâmetros foram heterogêneas em todos os grupos, independente da região geográfica (P>0,05). Quanto ao parasitismo (LDU), não houve diferença entre as amostras de fígado, especialmente quando se consideraram a classificação clínica e a região geográfica

[Effect of N-acetylcysteine on the egg granuloma in hepatic tissue of mice with Schistosomosis japonica].

OBJECTIVE: To study the effect of N-acetylcysteine (NAC) on the egg granuloma in hepatic tissue of mice infected with Schistosoma japonicum. METHODS: 36 mice were randomly divided into normal group, infected group and NAC group, each with 12 mice. The mice in the latter two groups were each infected with 25+/-2 cercariae of S. japonicum through the skin of abdomen. NAC solution was orally given to the mice of NAC group, 200 mg/kg, 2 times/d from the day of infection through to the 42nd day. Mice in the other 2 groups were given 2 ml normal saline daily. The mice were all sacrificed at the end of the 42nd day and their livers were collected for pathologic observation. Area of the egg granuloma was measured with computer image analysis software. Concentration of nitric oxide (NO) and reduced glutathione hormone (GSH), and the activity of glutathione peroxidase (GSH-PX) in serum and hepatic tissue, and the activity of inducible nitric oxide synthase (iNOS) in the hepatic tissue were all detected. RESULTS: Number of the single egg granuloma of "+,++,+++" grade were 1.80+/-0.25, 1.37+/-0.23 and 0.53+/-0.15 respectively in NAC treated group, which were less than those of infected group (3.70+/-0.28, 2.77+/-0.25 and 2.00+/-0.14 respectively) (P<0.05). The serum NO and GSH concentration was 0.53+/-0.17 and 229.66+/-9.47 respectively in NAC group, lower than those of infected group (2.64+/-0.31 and 312.47+/-18.55 respectively) (P<0.05), but its GSH-PX activity was 1101.99+/-140.81, higher than that of infected group (663.66+/-25.59) (P<0.05). The concentration of NO and GSH, and the activity of iNOS and GSH-PX in hepatic tissue of NAC group were 6.85+/-0.30, 13.44+/-0.40, 358.40+/-19.15 and 110.84+/-10.93 respectively, lower than those in infected group (8.26+/-1.69, 28.40+/-0.56, 1132.44+/-52.82 and 226.26+/-16.25 respectively) (P<0.05). CONCLUSION: NAC may have the effect of retarding pathological change of the liver, which may associate with the decrease of NO and GSH in serum and hepatic tissue and iNOS activity in the tissue.

[Examination of granuloma of revised cemented or cementless total hip arthroplasties using inductively coupled plasma atomic emission spectrometry (ICP-OES)]. / Atomemissionsspektralanalyse mit induktiv gekoppeltem Plasma (ICP-OES) von Granulomen zementierter und zementfreier Hüftendoprothesen.

INTRODUCTION: Aseptic loosening is the most common problem in total hip arthroplasty (THA). One main aspect is inflammatory reaction against wear particles of the prosthesis materials. Analysing failure mechanisms in THA analysis of the particles and their element distribution of revised granulomatous tissue is essential to improve materials used in THA. MATERIALS AND METHODS: 23 granulomas of revised THA due to aseptic loosening, 13 of which with metal on metal bearing (M/M), were analysed using inductively coupled plasma atomic emission spectrometry (ICP-OES). RESULTS: Elements Cr, Mn, Ni, Al, Cu, Zn, Cd, Ti, V, Zr, Nb and Fe could be detected. The maximum value of Cr was 23.88 ppb (parts per billion), Al 191.02 ppb, Ni 64.95 ppb and Zr 9.96 ppb. The highest value of Al could be found in cementless implants. The maximum value of the elements Cr and Ni could be detected in M/M. In cemented implants the highest value of Zr was found. DISCUSSION: The origin of Zr was the used bone cement in cemented THA. The elements Cr and Ni were significantly higher in M/M bearings. The highest value of Al was detected in granulomas of revised corund rough blasted cementless implants. The histopathologic findings of the revised M/M bearings have been published recently. Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES) could not show any differences of the alloying constituents in cases with or without allergic reactions. ICP-OES analysis seems to be not useful examination of histologic sections using SEM with cryotransfer unit.

[Pulmonary tumors]. / Lungentumoren.

Pulmonary nodules may be caused by true neoplasms of the airways, respiratory epithelium, vessels and connective tissue which are mainly malignant or metastatic. They may, however, also represent mainly inflammatory benign pseudotumours. Non-small cell lung cancer (NSCLC) usually presents as an ill-defined soft-tissue pulmonary nodule or mass, often without lymphadenopathy; endobronchial lesions are less common. Small cell lung cancer (SCLC) commonly presents with extensive lymph node and hematogenous metastases. Carcinoid tumors typically manifest as endobronchial lesions with secondary obstruction. Sarcomas are rare and show variable morphology. Metastases most commonly present as basal, peripheral, well-defined nodules. Granulomas often exhibit typical calcifications; hamartoma may also contain popcorn-type calcifications as well as fat. Pulmonary arteriovenous malformation is characterised by feeding artery and draining vein. Inflammatory nodules are well vascularized and may regress spontaneously; their differentiation from malignant lesions, however, is usually difficult.