Fibromixoma plexiforme del antro gástrico: descripción de 2 casos y revisión de la literatura / Plexiform fibromyxoma of the gastric antrum: a report of 2 cases and a review of the literature

El tumor miofibroblástico angiomixoide plexiforme o fibromixoma plexiforme es una neoplasia mesenquimal benigna, rara, recientemente descrita, que afecta al antro gástrico. Histológicamente presenta crecimiento plexiforme y está compuesta por células fibro/miofibroblásticas en un estroma mixoide, variable, con marcada trama capilar. En el presente artículo llevamos a cabo una revisión de la literatura y aportamos 2 casos adicionales en pacientes jóvenes (36 y 46 años) que consultaron por molestias gástricas inespecíficas y hemorragia digestiva alta. Ambas lesiones estaban situadas en la submucosa y en la capa muscular propia y presentaban un patrón de crecimiento plexiforme. Las células tumorales eran fusiformes y se disponían en el seno de una matriz mixoide abundante. La vascularización estaba constituida por numerosos vasos de pared fina y pequeño calibre. Con las técnicas de inmunohistoquímica, las células tumorales fueron positivas para actina de músculo liso, vimentina, caldesmón y desmina (un caso) y negativas para CD117, DOG1, EMA, S100, Beta-catenina y CD34. El estudio molecular no detectó mutaciones en los genes KIT y PDGFRA, en ninguno de los 2 casos. Hasta la fecha (4 años y 8 meses), ninguno de los pacientes ha desarrollado recidivas ni metástasis. El diagnóstico diferencial incluye una gran variedad de lesiones mixoides que pueden asentar o invadir la pared del estómago (GIST, tumor desmoide intraabdominal, pólipo fibroide inflamatorio, leiomioma-leiomiosarcoma, perineuroma, schwannoma y neurofibroma), pero solo el neurofibroma plexiforme comparte su característico patrón de crecimiento. Aunque en la revisión de la literatura hemos encontrado un total de 23 casos bajo la denominación de tumor gástrico miofibroblástico angiomixoide plexiforme o fibromixoma plexiforme, también hemos advertido que antes de la introducción de estos términos se habían descrito lesiones gástricas mixoides semejantes, no muy bien caracterizadas, que comparten mayoritariamente la localización antral gástrica, por lo que cabría especular sobre la posible existencia de una misma entidad con variable grado de diferenciación fibro/miofibroblástica y de patrón plexiforme, desarrollada probablemente en una población celular limitada exclusivamente al estómago(AU)

Plexiform, angiomyxoid myofibrobastic tumour, or plexiform fibromyoma, is a rare, recently described, benign neoplasm that affects the gastric antrum. Histologically the tumour has a plexiform growth pattern and is composed of fibro/myofibroblastic cells in a variable mixed stroma with a prominent capillary network. We have reviewed the literature and present 2 further cases occurring in young patients (36 and 46 years of age) who presented with gastric discomfort and upper gastrointestinal bleeding. Both lesions were located in the submucosa and muscularis and showed a plexiform growth pattern. Fusiform cells were found in an abundant myxoid extracellular matrix. Numerous small fine-walled blood vessels were present. Immunohistochemistry revealed positivity for smooth muscle actin, vimentin, h-caldesmon and desmin (in one case) and negativity for CD117, DOG1, EMA, S100, Beta-catenin and CD34. Molecular studies showed no mutations in the KIT and PDGFRA genes in either case. To date, neither of the patients has recurrences or metastases, 4 years and 8 months after diagnosis. Differential diagnosis includes a wide variety of myxoid lesions that may arise in or invade the stomach wall (GIST, intraabdominal desmoid tumour, inflammatory fibroid polyp, leiomyoma-leiomyosarcoma, perineuroma, schwannoma and neurofibroma), among these, plexiform neurofibroma is the only one showing the characteristic growth pattern. In our review of the literature, we found 23 cases described as gastric plexiform angiomyxoid myofibroblastic tumour, or gastric plexiform fibromyxoma. However, before the introduction of these terms, similar, if not completely characterized, gastric myxoid lesions had been described in the gastric antrum, suggesting that a single entity with a variable degree of fibro/myofibroblastic differentiation and a plexiform growth pattern might exist, perhaps developing in cells found only in the stomach(AU)

Linfadenitis cervical aislada por leishmaniasis con patrón «Piringer-Kuchinka-like» en un paciente inmunocompetente / Isolated cervical "Piringer-Kuchinka-like" lymphadenitis due to leishmaniasis in an immunocompetent patient

La linfadenitis cervical aislada por leishmaniasis es una forma de presentación peculiar que clínicamente simula una enfermedad maligna, fundamentalmente linfoma. Los criterios citológicos de la linfadenitis por leishmanias son característicos, y los cuerpos de Leishman-Donovan son la clave diagnóstica de esta entidad, con rasgos citológicos e histológicos similares a los descritos como linfadenitis de Piringer- Kuchinka. Presentamos este caso por tratarse de una presentación clinicopatológica inusual en una paciente inmunocompetente(AU)

Isolated cervical lymphadenitis due to leishmaniasis is rare and clinically may resemble malignant disease. The characteristic cytology with the presence of Leishman-Donovan bodies provides the most important diagnostic clue. Microscopically, it has similar features to toxoplasmosis (Piringer-Kuchinka) lymphadenitis. We present a case of leishmaniasis in an immunocompetent patient with an unusual clinicopathological presentation(AU)

[Colorectal melanoma: review of two distinct forms of presentation]. / Melanoma colorrectal: revisión de dos formas diferentes de presentación.

Malignant melanoma of the colon and rectum is an infrequent disease. Primary anorectal melanoma accounts for 0.1-4.6% of all malignant neoplasms of the anal canal. Melanoma metastatic to the colon is symptomatic only in 4.4% of patients with a primary melanoma at another site and most of these tumors are diagnosed postmortem. We report two cases of colorrectal malignant melanoma. The first case concerned a patient with rectal bleeding who was diagnosed with a rectal lesion compatible with melanoma. Abdominoperineal resection was performed due to positivity of the sentinel lymph node. We discuss the utility of sentinel lymph node detection in this kind of tumor. In the second case, we discovered a polyp compatible with metastatic melanoma in the transverse colon in a patient with a previous diagnosis of melanoma. In both surgical specimens, the diagnosis of melanoma was confirmed by positivity for protein S-100, Melan-A and HMB-45.

Melanoma colorrectal: revisión de dos formas diferentes de presentación / Colorectal melanoma: review of two distinct forms of presentation

El melanoma maligno colorrectal es una enfermedad infrecuente. El melanoma primario anorrectal se observa en el 0,1-4,6% de todos los tumores malignos anales. Por otro lado el melanoma metastásico en esta localización solo produce síntomas en el 4,4% de los pacientes con melanoma a otros niveles, siendo diagnosticado la mayoría de las veces post mórtem. Presentamos los casos de 2 pacientes con melanoma colorrectal. El primero de ellos muestra un paciente atendido por rectorragia en el que se diagnosticó una masa endoanal correspondiente a un melanoma y en el cual se practicó una resección abdominoperineal tras observar la positividad del ganglio centinela, discutiéndose su utilidad en este tipo de tumores. En el paciente del segundo caso se encontró una lesión polipoide en colon transverso correspondiente a una metástasis de un melanoma previamente diagnosticado. En ambas piezas histológicas la anatomía patológica fue característica con positividad para S-100, Melan-A y HMB-45 (AU)

Malignant melanoma of the colon and rectum is an infrequent disease. Primary anorectal melanoma accounts for 0.1-4.6% of all malignant neoplasms of the anal canal. Melanoma metastatic to the colon is symptomatic only in 4.4% of patients with a primary melanoma at another site and most of these tumors are diagnosed postmortem. We report two cases of colorrectal malignant melanoma. The first case concerned a patient with rectal bleeding who was diagnosed with a rectal lesion compatible with melanoma. Abdominoperineal resection was performed due to positivity of the sentinel lymph node. We discuss the utility of sentinel lymph node detection in this kind of tumor. In the second case, we discovered a polyp compatible with metastatic melanoma in the transverse colon in a patient with a previous diagnosis of melanoma. In both surgical specimens, the diagnosis of melanoma was confirmed by positivity for protein S-100, Melan-A and HMB-45 (AU)

Carcinosarcoma of the colon: report of a rare tumor.

Carcinosarcoma is a rare tumor that shows both epithelial and stromal malignant differentiation. Most reported cases of carcinosarcoma affect the female genital tract (and are called malignant mixed müllerian tumors), but there are also some isolated reports of cases affecting the lung and the head and neck area. Carcinosarcomas only rarely affect the gastrointestinal tract, mainly the esophagus. To the best of our knowledge, only eight cases of carcinosarcoma of the colon have been reported to date. For some lesions, the term 'sarcomatoid carcinoma' is preferred to 'carcinosarcoma', as both stromal and epithelial cells have shown cytokeratin expression on immunohistochemistry. The expression 'carcinosarcoma' should be applied only to those lesions, the stromal elements of which do not express epithelial markers. We report a new case of carcinosarcoma affecting the left colon. The most unique feature of this tumor is that it shows chondro-and osteosarcomatous differentiation, a feature that has been described previously in only one colonic carcinosarcoma. We discuss the histopathological and immunohistochemical features of this lesion as well as its possible histogenesis.