[Desmoplastic round cell tumor]. / Tumor desmoplásico de células redondas.

Desmoplastic small round cell tumor is a rare and very aggressive neoplasm that belongs to the family of "small round blue cell tumors". It has a higher incidence in males in the second decade of life. It is due to translocation t(11;22) (p13;q12). It can be located both in the abdomen and in the retroperitoneum and is characterized by nonspecific symptoms. The treatment is very varied and the one that guarantees the total cure of the patient has not yet been detected. The objective of this study is to expose a clinical case of desmoplastic tumor as an rare abdominal disease and its imaging expression.

El tumor desmoplásico de células pequeñas y redondas es una neoplasia poco frecuente y muy agresiva que forma parte de la familia de los "tumores de células pequeñas, redondas y azules". Presenta una mayor incidencia en el sexo masculino en la segunda década de la vida. Se debe a la translocación t(11;22) (p13;q12). Se puede localizar tanto en el abdomen como en el retroperitoneo caracterizándose por presentar síntomas inespecíficos. El tratamiento es muy variado y no se ha detectado todavía aquel que garantice la cura total del paciente. El objetivo del presente estudio es exponer un caso clínico de tumor desmoplásico como enfermedad abdominal infrecuente y su expresión imagenológica.

Tumor desmoplásico de células redondas / Desmoplastic round cell tumor

Resumen El tumor desmoplásico de células pequeñas y redon das es una neoplasia poco frecuente y muy agresiva que forma parte de la familia de los "tumores de célu las pequeñas, redondas y azules". Presenta una mayor incidencia en el sexo masculino en la segunda década de la vida. Se debe a la translocación t(11;22) (p13;q12). Se puede localizar tanto en el abdomen como en el re troperitoneo caracterizándose por presentar síntomas inespecíficos. El tratamiento es muy variado y no se ha detectado todavía aquel que garantice la cura total del paciente. El objetivo del presente estudio es exponer un caso clínico de tumor desmoplásico como enfermedad abdo minal infrecuente y su expresión imagenológica.

Abstract Desmoplastic small round cell tumor is a rare and very aggressive neoplasm that belongs to the family of "small round blue cell tumors". It has a higher incidence in males in the second decade of life. It is due to trans location t(11;22) (p13;q12). It can be located both in the abdomen and in the retroperitoneum and is character ized by nonspecific symptoms. The treatment is very varied and the one that guarantees the total cure of the patient has not yet been detected. The objective of this study is to expose a clinical case of desmoplastic tumor as an rare abdominal disease and its imaging expression.

Desmoplastic Small Round Cell Tumor: A Review of Main Molecular Abnormalities and Emerging Therapy.

Desmoplastic small round cell tumor (DSRCT) is an extremely rare, aggressive sarcoma affecting adolescents and young adults with male predominance. Generally, it originates from the serosal surface of the abdominal cavity. The hallmark characteristic of DSRCT is the EWSR1-WT1 gene fusion. This translocation up-regulates the expression of PDGFRα, VEGF and other proteins related to tumor and vascular cell proliferation. Current management of DSRCT includes a combination of chemotherapy, radiation and aggressive cytoreductive surgery plus intra-peritoneal hyperthermic chemotherapy (HIPEC). Despite advances in multimodal therapy, outcomes remain poor since the majority of patients present disease recurrence and die within three years. The dismal survival makes DSRCT an orphan disease with an urgent need for new drugs. The treatment of advanced and recurrent disease with tyrosine kinase inhibitors, such as pazopanib, sunitinib, and mTOR inhibitors was evaluated by small trials. Recent studies using comprehensive molecular profiling of DSRCT identified potential therapeutic targets. In this review, we aim to describe the current studies conducted to better understand DSRCT biology and to explore the new therapeutic strategies under investigation in preclinical models and in early phase clinical trials.

Cutaneous non-epitheliotropic large T-cell lymphoma in an English Bulldog

Cutaneous lymphoma is histologically classified in epitheliotropic and non-epitheliotropic, the first showing higher incidence in dogs, and the second, in cats. Non-epitheliotropic lymphoma presents lymphocyte aggregates in the dermis and subcutaneous tissue, however cutaneous annexes are not infiltrated. It is usually more aggressive than epitheliotropic lymphomas. The aim of this study was to report a case of non-epitheliotropic lymphoma in a 9-year-old, female, English Bulldog presented with non-ulcerated skin nodules adhered to deep tissues. Microscopic and immunophenotypic features supported the diagnosis of non-epitheliotropic large T-cell lymphoma. Treatment was initiated with modification of the LOPP protocol, replacing procarbazine by dacarbazine (600 mg/m²) for up to six cycles, with a three-month survival. In the 11th week of treatment, after recurrent episodes of vomiting and diarrhea, abdominal ultrasound was performed and revealed an infiltrative mass in the stomachs greater curvature topography, showing an expansive and accentuated increase in one week, when euthanasia was elected.(AU)

Cutaneous non-epitheliotropic large T-cell lymphoma in an English Bulldog

Cutaneous lymphoma is histologically classified in epitheliotropic and non-epitheliotropic, the first showing higher incidence in dogs, and the second, in cats. Non-epitheliotropic lymphoma presents lymphocyte aggregates in the dermis and subcutaneous tissue, however cutaneous annexes are not infiltrated. It is usually more aggressive than epitheliotropic lymphomas. The aim of this study was to report a case of non-epitheliotropic lymphoma in a 9-year-old, female, English Bulldog presented with non-ulcerated skin nodules adhered to deep tissues. Microscopic and immunophenotypic features supported the diagnosis of non-epitheliotropic large T-cell lymphoma. Treatment was initiated with modification of the LOPP protocol, replacing procarbazine by dacarbazine (600 mg/m²) for up to six cycles, with a three-month survival. In the 11th week of treatment, after recurrent episodes of vomiting and diarrhea, abdominal ultrasound was performed and revealed an infiltrative mass in the stomach’s greater curvature topography, showing an expansive and accentuated increase in one week, when euthanasia was elected.

Histological classification and expression of markers of canine mast cell tumors.

BACKGROUND AND AIM: Mast cell tumors (MCTs) are malignant neoplasms that are common in dogs. Their biological behavior is variable and unpredictable. The aim of the present study was to analyze the histological classification and expression of markers of canine MCTs. MATERIALS AND METHODS: Thirty samples of canine MCTs were graded according to the histological classification methods of Patnaik and those of Kiupel. The expression of phosphoprotein 53 (p53) and c-kit proteins was quantified by immunohistochemistry using image processing software, ImageJ - a public domain computer program, developed at the National Institutes of Health. RESULTS: It was possible to determine the grade of 100% of the samples. According to Patnaik's classification, 20.00% of the samples were Grade 1, 43.30% were Grade 2, and 36.70% were Grade 3. According to Kiupel's classification, 56.67% of the samples were of high intensity and 43.33% were of low intensity. Grade 1 tumors had the highest expression of p53 and c-kit, and Grade 2 had the lowest expression. The results showed that it is necessary to perform both histological grading methods. The classification into high and low intensity may provide more consistent results than the three-level grading system. However, a smaller number of categories, although it facilitates the classification, may not be sufficient for the prognosis. CONCLUSION: Quantitative evaluation of p-53 and c-kit expression is a useful tool to increase the accuracy of the analysis and to aid in choosing the treatment method for canine MCTs. Histological grading should be combined with other diagnostic methods.

Tumor desmoplásico de célula pequeña y redonda paratesticular/testicular: reporte de caso y revisión de la literatura / Paratesticular/testicular desmoplastic round small cell malignant tumor: case report and literature review

Resumen El tumor desmoplásico de célula redonda y pequeña (TDCRP) es una patología neoplásica maligna agresiva y poco común. Afecta predominantemente a hombres entre la segunda y tercera década de la vida. Los pacientes que la padecen tienen un pronóstico pobre, con una supervivencia global a 5 años de hasta el 30%. Por lo general se presenta como una masa en la cavidad abdominal, frecuentemente multifocal. Para su tratamiento se recomienda un enfoque multimodal con cirugía, quimioterapia y radioterapia. Poco más de 20 casos de TDCRP a nivel testicular/paratesticular se han reportado en la literatura. A continuación, se presenta un caso ilustrativo en esta localización, se discute el caso y se realiza revisión de la literatura.

Abstract Desmoplastic small round cell tumor (DSRCT) is an aggressive and rare malignant neoplasm. It mainly affects young men in their twenties and thirties. Patients with it have a poor prognosis, with a 5-year survival rate of up to 30%. It generally presents as a mass in the abdominal cavity, often multifocal. A multimodal approach is recommended for its treatment, with surgery, chemotherapy, and radiotherapy. Just over 20 cases of testicular/paratesticular DSRCT have been reported in the literature. Below, we present an illustrative case in this location, we discuss the case and review the literature.

Desmoplastic small round cell tumor of the ovary: A case report with a new modality of treatment and review of the literature

Abstract Objective Desmoplastic small round cell tumor (DSRCT) is a rare intraabdominal neoplasm that grows along serosal surfaces and is primarily found in young men. To Keywords date, only 16 cases of ovarian DSRCT have been previously reported in women in the English literature, and no large population-based studies on this topic exist. Case Report We report the case of a 19-year-old virgo with unremarkable past medical history, initially presented with abdominal fullness. After being treated with the optimal treatment modality (primary and secondary surgical debulking, unique chemotherapy, protocol and adjuvant radiotherapy), the patient has remained without tumor disease for 40 months. Conclusion Although the best therapy for patients with DSRCT has yet to be determined, combining complete surgical resection, adjuvant chemotherapy, and radiotherapy is required to prolong survival and to achieve proper quality of life.

Tumor desmoplásico de células pequeñas y redondas. Presentación de caso y revisión de la literatura / Desmoplastic Small Round Cell Tumor. A Case Report and Literature Review

El tumor desmoplásico de células pequeñas y redondas (TDCPR) es una neoplasia maligna rara, con curso clínico agresivo y mortalidad elevada. Se presenta el caso de un hombre de 21 años de edad, quien consultó por dolor abdominal de intensidad moderada, irradiado al flanco derecho, fiebre y pérdida de peso. En tomografía abdominal con medio de contraste se documentó una gran masa intraperitoneal con áreas de necrosis central y extensión a la pelvis, además de lesiones hepáticas de aspecto neoplásico secundario. El diagnóstico se confirmó mediante biopsia percutánea guiada por ultrasonido, que mostró extensa infiltración por tumor maligno, constituido por células con núcleos vesiculosos de cromatina clara, citoplasma eosinófilo e inmunohistoquímica compatible con dicho tumor. En este artículo se hace una confrontación del caso con los hallazgos descritos en otras series publicadas en la literatura y una revisión clínica del tema.

Desmoplastic small round cell tumor (DSRCT) is a rare malignant neoplasm with an aggressive clinical course and high mortality. The case of a 21-year-old man is presented, who consulted for abdominal pain of moderate intensity radiating to the right flank, fever and weight loss. Contrast abdominal tomography was performed, documenting a large intraperitoneal mass with areas of central necrosis and extension to the pelvis, in addition to secondary neoplastic liver lesions. The diagnosis was confirmed by ultrasound-guided percutaneous biopsy, which reported extensive infiltration by malignant tumor, consisting of cells with vesicular nuclei of clear chromatin, eosinophilic cytoplasm and immunohistochemistry compatible with said tumor. This case report is compared with the findings described in other series published in the literature and a clinical review of the subject is made.

Multimodal treatment of an extremely rare desmoplastic small round cell tumor primary to the brachial plexus - A case report and review of literature.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive malignant neoplasm typically located in the abdomen or pelvis. Other possible locations are the chest, pleura, scrotum, and central nervous system. DSRCT originally arising from the brachial plexus (BP) is extremely rare, to the best of our knowledge, only two cases have been previously described in the English scientific literature. CASE DESCRIPTION: The authors present one new case of DSRCT arising from the left BP, the first in this location with rapid progression and in a female patient. We also highlight the importance of multimodal therapy, which included resection and both adjuvant radiation and chemotherapy. Macroscopic and microscopic characteristics of the lesion are detailed, as well as the patient's status at 56-month follow-up. CONCLUSION: For primary BP DSRCT, aggressive subtotal resection followed by radiation and chemotherapy can be satisfactory for disease control and for maintaining or improving the neurological status.

Irinotecan and vincristine for the treatment of refractory desmoplastic small round cell tumor in a developing country: a case report.

INTRODUCTION: Desmoplastic small round cell tumor is an extremely rare and aggressive cancer that affects mainly adolescents and young adults. Despite multiple therapeutic strategies, most patients have resistant disease with very poor survival rates. CASE PRESENTATION: We present a case of a 10-year-old Caucasian boy with a desmoplastic small round cell tumor refractory to conventional treatment who exhibited a good response to alternative treatment. With use of irinotecan and vincristine in association with radiation therapy, a reduction of 96.9% of the dimensions of the target lesions compared with the initial image was observed. CONCLUSION: This chemotherapy regimen, in association with radiation therapy, demonstrated efficacy for refractory desmoplastic small round cell tumor in our patient, and it is cost-effective.

A genomic case study of desmoplastic small round cell tumor: comprehensive analysis reveals insights into potential therapeutic targets and development of a monitoring tool for a rare and aggressive disease.

BACKGROUND: Genome-wide profiling of rare tumors is crucial for improvement of diagnosis, treatment, and, consequently, achieving better outcomes. Desmoplastic small round cell tumor (DSRCT) is a rare type of sarcoma arising from mesenchymal cells of abdominal peritoneum that usually develops in male adolescents and young adults. A specific translocation, t(11;22)(p13;q12), resulting in EWS and WT1 gene fusion is the only recurrent molecular hallmark and no other genetic factor has been associated to this aggressive tumor. Here, we present a comprehensive genomic profiling of one DSRCT affecting a 26-year-old male, who achieved an excellent outcome. METHODS: We investigated somatic and germline variants through whole-exome sequencing using a family based approach and, by array CGH, we explored the occurrence of genomic imbalances. Additionally, we performed mate-paired whole-genome sequencing for defining the specific breakpoint of the EWS-WT1 translocation, allowing us to develop a personalized tumor marker for monitoring the patient by liquid biopsy. RESULTS: We identified genetic variants leading to protein alterations including 12 somatic and 14 germline events (11 germline compound heterozygous mutations and 3 rare homozygous polymorphisms) affecting genes predominantly involved in mesenchymal cell differentiation pathways. Regarding copy number alterations (CNA) few events were detected, mainly restricted to gains in chromosomes 5 and 18 and losses at 11p, 13q, and 22q. The deletions at 11p and 22q indicated the presence of the classic translocation, t(11;22)(p13;q12). In addition, the mapping of the specific genomic breakpoint of the EWS-WT1 gene fusion allowed the design of a personalized biomarker for assessing circulating tumor DNA (ctDNA) in plasma during patient follow-up. This biomarker has been used in four post-treatment blood samples, 3 years after surgery, and no trace of EWS-WT1 gene fusion was detected, in accordance with imaging tests showing no evidence of disease and with the good general health status of the patient. CONCLUSIONS: Overall, our findings revealed genes with potential to be associated with risk assessment and tumorigenesis of this rare type of sarcoma. Additionally, we established a liquid biopsy approach for monitoring patient follow-up based on genomic information that can be similarly adopted for patients diagnosed with a rare tumor.

Requirement for novel surgical and clinical protocols for the treatment of desmoplastic small round cell tumor: A report of two cases and a review of the literature.

Desmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive neoplasm that was initially described in 1989. DSRCT predominantly affects young men and typically occurs in the intra-abdominal area. The present study describes the cases of two patients with DSRCT. The first patient was a 23-year-old male who presented with abdominal pain in the right flank, coupled with difficulty urinating and bowel dysfunction. The second patient was 12-year-old female who presented with abdominal pain, emesis and loss of appetite. A computed tomography scan of the abdomen revealed the presence of an extensive pelvic mass in each patient, however, a visceral origin was not clearly identifiable in the first patient. In the second patient, a large soft-tissue tumor was located posterior to the pancreatic tail and the stomach, with no anatomical line visible between the stomach and splenic vein. Ultrasound-guided biopsy in the first patient and videolaparoscopy in the second patient followed by immunohistochemical analysis clarified the presence of a malignant neoplasm composed of small, blue, round cells. Due to right ureter involvement and hydronephrosis in the first patient, a treatment strategy of surgical debulking of the tumor was selected. The surgical procedure involved en bloc resection of the lesion associated with a pelvic peritonectomy, followed by post-operative radiotherapy. However, the second patient exhibited extensive disease, therefore, a chemotherapeutic protocol of vincristine, doxorubicin and cyclophosphamide, as well as radiation therapy, was scheduled. Disease relapse was observed in the abdominal cavity of the first patient after one year, while the second patient remains asymptomatic. Following analysis of present two cases, it was concluded that aggressive treatment regimens may induce tumor regression. However, relapse of the disease is frequent and long-term survival is rare with the currently available therapeutic strategies.

[Intra-abdominal desmoplastic small round cell tumour]. / Tumor intraabdominal desmoplásico de células pequeñas y redondas.

BACKGROUND: The desmoplastic small round cell tumour is a rare and aggressive intra-abdominal neoplasia, with only 200 cases reported, and a higher incidence in men and predilection for the second decade of life. Histologically characterized by the presence of small nests of undifferentiated tumour cells, wrapped in fibrous desmoplastic stroma. CLINICAL CASE: A 24 year old male started with abdominal pain of 4 weeks onset in the right upper quadrant, colic type, sporadic, self-limiting and accompanied by early satiety, decreased appetite, and involuntary weight loss of 10 kg in 3 months. At the time of admission the abdomen was globular, with decreased peristalsis, soft, depressible. Computed tomography of the abdomen showed multiple enlarged lymph nodes in the abdominal-pelvic cavity. A laparotomy was performed, with a subsequent omentum resection due to the presence of multiple tumours, which microscopically were characterised by groups of small, round, blue cells, separated by a desmoplastic stroma. The immunohistochemistry was positive for desmin (> 75%), epithelial membrane antigen (> 75%), CD99 (> 50%), and S100 (25%), concluding with an abdominal tumour of small, round, blue cells as a diagnosis. Chemotherapy treatment was initiated based on IMAP plus GM-CSF. CONCLUSIONS: The desmoplastic small round cell tumour is a rare neoplasia, with diagnostic complexity and a lethal course. Its clinical presentation is unspecific. Histologically, it is classified as an aggressive soft tissue sarcoma that shares similar characteristics with the family of the small and blue cells tumours.

Unusual morphology of desmoplastic small round cell tumor from an ascitic fluid in the postchemotherapy setting.

Desmoplastic small round cell tumor (DSRCT) is a malignant neoplasm that most often presents in male adolescents as an abdominal mass. Cytological features have been previously described, but only two reports noted post chemotherapy changes on effusions. We report a case of a 15-year-old male with DSRCT status postchemotherapy that presented with ascitis. Unusual morphology was seen: Numerous malignant large and single cells with prominent nucleoli and abundant cytoplasm in a background without the stroma, occasional mitosis, and the abundant apoptosis. Cell block immunocytochemistry was confirmatory. Awareness of the postchemotherapy changes in this tumor will allow us to diagnose recurrence.

Tumor desmoplásico de pequenas células redondas: relato de caso / Desmoplastic small round cell tumor: a case report

O tumor desmoplásico de pequenas células redondas (TDCPR) é uma neoplasia de ocorrência rara, descrita em 1987 por Sesterhenn et al. Atualmente existem cerca de 101 casos na literatura consultada. Os autores relatam um caso de TDCPR intra-abdominal em paciente de 53 anos de idade, portador de massa palpável em epigástrio, assintomático.A propedêutica evidenciou múltiplas lesões expansivas de dimensões variadas comprometendo a cavidade peritoneal. Foi submetido à laparotomia exploradora, sendo possível apenas a cirurgia citorredutora. São descritos os achados intraoperatórios, tomográficos, bem como os aspectos macroscópicos e imuno-histoquímicos. O paciente manteve acompanhamento no Serviço de Oncologia. Faleceu meses após a cirurgia.

The desmoplastic small round cell tumor (DSRCT) is a neoplasm of rare occurrence, described in 1987 by Sesterhennet al. Currently, there are about 101 cases described in the consulted literature. The authors report a case of intra-abdominal DSRCT in a 53-year-old patient, carrier of a palpable mass in epigastrium, asymptomatic. The propaedeutics showed multiple expansive lesions of varying dimensions compromising the peritoneal cavity. The patient was referred to exploratory laparotomy; only cytoreductive surgery was possible. The intraoperative findings are described, tomographic, and macroscopic and immunohistochemical aspects. The patient was followed up at the Oncology Service. He died months after surgery.

Desmoplastic small round cell tumor: report of 2 cases treated with chemotherapy alone or in combination with bevacizumab.

Here, we present 2 case reports of patients with desmoplastic small round cell tumor (DSRCT), a very rare and aggressive mesenchymal cancer, and we discuss 2therapeutic options for this sarcoma. This report focuses on men aged 22 and 37 years, respectively. The first patient presented with an abdominopelvic mass which was not suitable for surgery. He underwent chemotherapy (adriblastina and cisplatin) with a brief partial remission and survival time of 13 months. The second patient presented with an abdominal mass and underwent partial resection. He received chemotherapy and bevacizumab, resulting in a partial remission and a survival time of 34 months. The extent of surgery and monoclonal antibody use probably had a positive impact on survival. It is necessary to include specific targeted therapies in an attempt to improve survival. Surprisingly, positron emission tomography was not effective in restaging of the second patient, emphasizing the importance of computed tomography or magnetic resonance in DSRCT.

Immunohistochemical study of genital and extragenital forms of canine transmissible venereal tumor in Brazil / Estudo imuno-histoquímico de formas genitais e extragenitais do tumor venéreo transmissível canino no Brasil

Aiming to provide insight and discussing the problems related to the diagnosis and differential diagnosis of canine transmissible venereal tumor (CTVT), especially in its extragenital form, immunohistochemical evaluation was performed and a comparison was established by analysis of the microscopic appearance of 10 genital CTVTs and 13 exclusively extragenital CTVTs previously diagnosed by cytology and histopathology. CTVTs samples were incubated with biotinylated antibodies raised against specific membrane (anti-macrophage) and cytoplasmic antigens (anti-lysozyme, anti-S-100 protein, anti-vimentin and anti-CD18) and subsequently developed using streptavidin-biotin peroxidase and streptavidin-biotin-alkaline phosphatase methods. A strong reactivity with the anti-vimentin antibody was found in 100% of the tumors tested (22/22). No reactivity was found for the anti-lysozyme, anti-macrophage, anti-S-100 protein and anti-CD18. No histopathological or immunoreactivity differences between genital and extragenital CTVTs were found. These findings do not corroborate the hypothesis of histiocytic origin of CTVT (no reactivity to anti-lysozyme, anti-macrophage and anti-CD 18 antibodies). In addition, the antibody panel used is useful to narrow the differential diagnosis for lymphomas, histiocytic tumors, amelanotic melanomas, and poorly differentiated epithelial neoplasias, among others.(AU)

Com a finalidade de fornecer subsídios e discutir os problemas referentes ao diagnóstico e ao diagnóstico diferencial do tumor venéreo transmissível canino (TVTC), principalmente em sua forma extragenital, foi realizada a avaliação imuno-histoquímica e estabelecido termo de comparação com o aspecto microscópico em 10 TVTCs genitais e em 13 exclusivamente extragenitais previamente diagnosticados através de citologia e histopatologia. Os TVTCs foram testados para reagentes específicos de antígenos de membrana (anti-macrófago) e citoplasmáticos (anti-lisozima, anti-proteína S-100, anti-alfa-1-antitripsina, anti-vimentina e anti-CD18) com a utilização da técnica complexo avidina-biotina-peroxidase e estreptavidina-biotina-fosfatase Em 100% dos tumores testados (22/22) com anticorpo anti-vimentina houve forte imuno-reatividade. Não houve reatividade para os anticorpos anti-lisozima, anti-macrófago, anti-proteína S-100 e anti-CD18. Não houve diferença histopatológica e de imuno-reatividade entre os TVTCs genitais e extragenitais. Estes achados indicam que os TVTCs avaliados não são de origem histiocítica (ausência de reatividade dos anticorpos anti-lisozima, anti-macrófago e anti-CD18). O painel de anticorpos utilizado é útil para o diagnóstico diferencial deste tumor com linfomas, tumores histiocíticos, melanomas amelanóticos e neoplasias de origem epitelial pobremente diferenciadas, entre outros.(AU)

Immunohistochemical study of genital and extragenital forms of canine transmissible venereal tumor in Brazil / Estudo imuno-histoquímico de formas genitais e extragenitais do tumor venéreo transmissível canino no Brasil

Aiming to provide insight and discussing the problems related to the diagnosis and differential diagnosis of canine transmissible venereal tumor (CTVT), especially in its extragenital form, immunohistochemical evaluation was performed and a comparison was established by analysis of the microscopic appearance of 10 genital CTVTs and 13 exclusively extragenital CTVTs previously diagnosed by cytology and histopathology. CTVTs samples were incubated with biotinylated antibodies raised against specific membrane (anti-macrophage) and cytoplasmic antigens (anti-lysozyme, anti-S-100 protein, anti-vimentin and anti-CD18) and subsequently developed using streptavidin-biotin peroxidase and streptavidin-biotin-alkaline phosphatase methods. A strong reactivity with the anti-vimentin antibody was found in 100% of the tumors tested (22/22). No reactivity was found for the anti-lysozyme, anti-macrophage, anti-S-100 protein and anti-CD18. No histopathological or immunoreactivity differences between genital and extragenital CTVTs were found. These findings do not corroborate the hypothesis of histiocytic origin of CTVT (no reactivity to anti-lysozyme, anti-macrophage and anti-CD 18 antibodies). In addition, the antibody panel used is useful to narrow the differential diagnosis for lymphomas, histiocytic tumors, amelanotic melanomas, and poorly differentiated epithelial neoplasias, among others.

Com a finalidade de fornecer subsídios e discutir os problemas referentes ao diagnóstico e ao diagnóstico diferencial do tumor venéreo transmissível canino (TVTC), principalmente em sua forma extragenital, foi realizada a avaliação imuno-histoquímica e estabelecido termo de comparação com o aspecto microscópico em 10 TVTCs genitais e em 13 exclusivamente extragenitais previamente diagnosticados através de citologia e histopatologia. Os TVTCs foram testados para reagentes específicos de antígenos de membrana (anti-macrófago) e citoplasmáticos (anti-lisozima, anti-proteína S-100, anti-alfa-1-antitripsina, anti-vimentina e anti-CD18) com a utilização da técnica complexo avidina-biotina-peroxidase e estreptavidina-biotina-fosfatase Em 100% dos tumores testados (22/22) com anticorpo anti-vimentina houve forte imuno-reatividade. Não houve reatividade para os anticorpos anti-lisozima, anti-macrófago, anti-proteína S-100 e anti-CD18. Não houve diferença histopatológica e de imuno-reatividade entre os TVTCs genitais e extragenitais. Estes achados indicam que os TVTCs avaliados não são de origem histiocítica (ausência de reatividade dos anticorpos anti-lisozima, anti-macrófago e anti-CD18). O painel de anticorpos utilizado é útil para o diagnóstico diferencial deste tumor com linfomas, tumores histiocíticos, melanomas amelanóticos e neoplasias de origem epitelial pobremente diferenciadas, entre outros.

Morphological patterns and malignancy criteria of transmissible venereal tumor in cytopathological and histopathological exams / Padrões morfológicos e critérios de malignidade do tumor venéreo transmissível aos exames citopatológico e histopatológico

The aim of this study was to identify morphological patterns and malignancy criteria of the TVT in cytopathological and histopathological evaluations and relate these characteristics to clinical evolution and response to chemotherapy. Regarding studied animals, sixteen dogs were female and four were male. The age of the animals ranged between one and ten years old. Considering breed, 80% of the dogs were mongrel dogs and 20% were of other breeds. It was found that the cytological samples allowed a better characterization of the cell type than histological ones. The plasmacytoid was the most common morphological type of TVT, followed by the lymphocytoid and mixed standards. There was no difference among the scores for the malignancy criteria and morphological types of TVT. Regarding response to chemotherapy, no morphological type of the TVT showed any difference, but the TVT presents morphological peculiarities that may interfere with tumor behavior, especially those related to increased aggressiveness and that are observed in the plasmacytoid TVT.(AU)

Este estudo teve por objetivo identificar os padrões morfológicos e os critérios de malignidade do TVT aos exames citológico e histopatológico e relacionar essas características à evolução clínica e à resposta à quimioterapia. Dos ani- mais estudados, dezesseis cães eram fêmeas e quatro machos. A idade dos animais variou entre um e dez anos de idade. Quanto à raça, 80% dos cães eram sem raça definida e 20% de outras raças. Constatou-se que as amostras citológicas permitiram melhor caracterização do tipo celular do que as histológicas. O TVT tipo plasmocitoide foi o de maior ocor- rência, seguido pelos padrões linfocitoide e misto. Não houve diferença entre os escores estabelecidos para os critérios de malignidade e os tipos do TVT. Nenhum tipo morfológico do TVT diferiu quanto à resposta quimioterápica, mas o TVT apresenta particularidades morfológicas que podem interferir no comportamento tumoral, especialmente aquelas relacionadas à maior agressividade, e que são observadas no TVT plasmocitoide.(AU)