Melanoma maligno gastrointestinal de origen primario desconocido: reporte de caso / A case report of malignant gastrointestinal melanoma of unknown primary origin

Resumen Una de las características inusuales del melanoma cutáneo es la capacidad de metastatizar en el intestino delgado. A menudo se diagnostica durante la autopsia, en la cual se ha encontrado depósitos metastásicos en el 50%-60% de los casos, pero menos del 2% al 4% de los pacientes con diagnóstico de melanoma tiene metástasis gastrointestinal (GI) durante el curso de la enfermedad y entre el 4%-9% de casos de melanoma GI tiene un primario desconocido. La rápida identificación y resección del melanoma en el tracto digestivo podría mejorar la tasa de supervivencia en aquellos pacientes en los que se presentan complicaciones, como obstrucción intestinal. Se presenta un caso clínico de melanoma gastrointestinal de origen primario desconocido. El porcentaje de este tipo de casos es poco frecuente. La paciente presentó cuadro clínico de náuseas, hiporexia, epigastralgia, fatiga, parestesias en región dorsal derecha y disminución de 9 kilogramos en 3 semanas. Le realizaron tomografía computarizada (TAC) de abdomen contrastado, que reportó 3 lesiones en hígado de predominio isodenso en el parénquima, con algunas áreas de menor densidad al interior, localizadas en los segmentos 2, 5, 7 y 8 del hígado al que se le realizó la biopsia. Se llevó a cabo endoscopia de vías digestivas altas con biopsia de 2 lesiones hiperpigmentadas en la segunda porción de duodeno. El examen histopatológico de las biopsias evidenció melanoma maligno. Se excluyeron todas las localizaciones típicas de melanoma primario durante el procedimiento diagnóstico.

Abstract One of the unusual characteristics of cutaneous melanoma is its ability to metastasize in the small intestine. It is often diagnosed during autopsies of cutaneous melanoma patients. Metastatic deposits have been found in 50% to 60% of these autopsies, but less than 2% to 4% of patients diagnosed with melanoma have gastrointestinal metastasis during the course of the disease. Between 4% and 9% of gastrointestinal melanoma cases have unknown primary tumors. Rapid identification and resection of melanoma in the digestive tract could improve the patient survival rate and prevent complications such as intestinal obstructions from occurring. We present a rare clinical case of gastrointestinal melanoma of unknown primary origin. The patient had a clinical picture of nausea, hyporexia, epigastralgia, fatigue, paresthesias in the right dorsal region and had lost nine kilograms in three weeks. An abdominal CT scan showed three predominantly isodense liver lesions in the parenchyma, with some areas of lower density located in segments 2,5,7 and 8 of the liver. These were biopsied. Upper digestive tract endoscopy took biopsy samples of two hyperpigmented lesions in the second portion of the duodenum. Histopathological examination showed malignant melanoma. All typical locations of primary melanoma were excluded during the diagnostic procedure.

Hemispheric asymmetry in lexical decisions: the effects of grammatical class and imageability.

It has been suggested that neural systems for lexical processing of nouns and verbs are anatomically distinct. The aim of the present study was to investigate if brain asymmetry for the processing of these two grammatical classes is also different. Neurologically intact adults performed a lateralized lexical decision task with grammatically unambiguous words of high, medium, and low degrees of imagery. For error scores a right visual field (RVF) advantage and an overall effect of imageability were obtained. For latency scores grammatical class and imageability modified visual field differences: in the noun class a RVF advantage was obtained only for low imagery nouns, while for the verbs the RVF advantage was present for both medium and low imagery verbs. These results suggest that the participation of right hemisphere neural systems in the processing of verbs is more limited than in the processing of nouns.

Blood types in cattle of Iberian ancestry and in Holsteins at various altitudes.

Gene frequencies of RBC antigens were determined in Holsteins and Colombian (criollas) cattle living at 3,000 m, and in cattle descended from fighting bulls (Vacas de lidia) living at 2,500 m. These frequencies were compared with those of Holsteins, cattle native to Florida (scrub cattle), longhorns, and native cattle from Brazil (caracu cattle) living at sea level. The criollas, Vacas de lidia, scrub cows, longhorns, and caracu are descendants of original Iberian stock introduced to the Americas. We found that despite common ancestry (scrub cattle, long-horns, criollas, and caracu), genetic differences may have been derived through years of demographic isolation. The most remarkable blood-group differences were found in the high prevalence of the B system phenogroup (heritable group of antigenic factors) BQA'G'34 in the Vacas de lidia, and of the S system phenogroup U1H' in these cattle and in caracu. Furthermore, the gene frequencies differed in the Holsteins maintained at moderately high altitude (descended from Holsteins kept at sea level), and may have been reflective of the need to adapt to moderately high altitude and chronic hypoxemic conditions. Blood group polymorphism was found in all groups of cattle, although it was reduced in the Vacas de lidia, possibly because their breeding has been carefully controlled and they appear to be highly inbred.

Blood biochemical characteristics of cattle at sea level and at moderately high altitude (3,000 m).

We investigated the biochemical composition of blood from Holstein cows, native breed (criollas), and cows descended from fighting bulls (Vacas de lidia) raised at an altitude of 3,000 m (moderately high altitude, MHA), and compared the results with those from Holsteins and cows of similar genetic ancestry as the criollas (scrub cows), both raised at sea level (SL), to determine blood biochemical values characteristic of adaptation to high altitude. Only potassium and calcium concentrations were similar among groups. Glucose concentration was lower in MHA cows, with the exception of Vacas de lidia. Serum bicarbonate concentration was lower in MHA cows; this finding can be explained by hyperventilation in the hypoxic environment. Serum magnesium concentration was lower in SL and MHA Holsteins than in other groups. Serum phosphate concentration was lower in scrub cows, MHA Holsteins, and criollas than in other groups. Cholesterol concentrations were lower in SL Holsteins, whereas triglycerides were higher in scrub cows and MHA Vacas de lidia. Concentration of high-density lipoprotein was significantly greater in Vacas de lidia and less in MHA criollas than in the other groups. Uric acid and total protein were higher in MHA groups. Using radioimmunoassay for human proteins, thyroxine-binding globulin was undetectable. Total and free thyroxine and free triiodothyronine were higher in scrub cows, followed by Vacas de lidia; lower values were detected in SL and MHA Holsteins and MHA criollas.