[Multicentric inflammatory pseudotumor with asynchronic presentation in meninges, liver, spleen and lymph nodes in a patient with seronegative spondiloarthropathy. Case report and review of the literature]. / Pseudotumor inflamatorio multicéntrico con presentación asincrónica en meninges, hígado, bazo y ganglios linfáticos en una paciente con espondiloartropatía seronegativa. Presentación de un caso y revisión de la bibliografía.

INTRODUCTION: Inflammatory pseudotumor is a reactive process in which the etiology and pathogenesis are not well defined, that can be found in any location. The cases with central nervous system affection have been described in meninges, brain, choroid plexus and cranial and spinal nerves. Multicentric cases, synchronous and asynchronous have been described. CASE REPORT: A 45 years-old woman with a rheumatologic disease (a seronegative spondiloarthropathy) who developed an inflammatory pseudotumor in spleen, liver and abdominal lymph nodes in 1995, associated to fever of unknown origin, six years later she presented with an inflammatory pseudotumor of the meninges in the convexity of the right frontoparietal region, with fever, malaise, and increase of globular sedimentation rate, microcytic hypochromic anemia and thrombocytosis. CONCLUSION: The clinicopathologic features of this lesion are revised, including the different theories in regard to the etiology and pathogenesis, and the role of cytokines produced by inflammatory cells in the tumor.

[An atypical rhabdoid/teratoid tumor. A presentation of three cases and review of the literature]. / Tumor rabdoide/teratoide atípico. Presentación de tres casos y revisión de la literatura.

INTRODUCTION: The atypical rhabdoid/teratoid tumor of the central nervous system (CNS) has emerged from a variant of medulloblastoma to become a distinctive clinico-pathological condition over the past ten years. This is more than simply nosological importance, since the five year survival expected in medulloblastomas is considerably better than the 11 months (average) seen in rhabdoid/teratoid tumors. OBJECTIVE: To describe the main clinico-pathological characteristics of a recently recognized condition, emphasizing its polymorphism and differential diagnosis. PATIENTS AND METHODS: We report the clinical, radiological, cytohistopathological and immunohistopathological aspects of three atypical rhabdoid/teratoid tumors diagnosed in the Hospital A.B.C. of Mexico City. RESULTS: The three tumors were seen in boys aged 18 months, 5 years and 14 years, localized to the right cerebellum, left cerebral hemisphere and left cerebellum, respectively. Different markers were shown including: vimentin, cytokeratin, epithelial membrane antigen, gliofibrillare acid protein, synaptophysin, alpha fetoprotein, S100, (HHF-35) actin, cromogranin, neurofilaments, human chorionic gonadotrophin, placental alkaline phosphatase, desmin, CD99 and carcinoembryonary antigen. We established the morphological similarities and differences in our cases, and noted the profuse vascular proliferation which in one case resembled vascular neoplasia. We compared our results with other published cases. CONCLUSIONS: The atypical rhabdoid/teratoid tumor of the CNS may easily be confused with other primary or metastatic tumors since the rhabdoid characteristics do not only occur in this tumor. Also the rhabdoid aspect may be less marked and in some cases does not predominate. Some zones of the tumor may be identical to other embryonic tumors of the CNS and the immunophenotype be superimposed on that of other neoplasias of the nervous system.

[Primary melanoma of the esophagus. Unusual case with Barrett's esophagus]. / Melanoma primario en el esófago. Caso inusual con esófago de Barrett.

OBJECTIVE: To present a rare entity of difficult preoperative diagnosis. BACKGROUND: Primary malignant melanoma of the esophagus represents 0.1% of all malignant tumors in this organ. It has been described in association with esophageal melanocytosis and melanosis with a clinic behavior similar to other neoplasm in the esophagus, but is more aggressive and fatal. By endoscopy, it usually appears as a vegetant, non-obstructive lesion, with dark pigmentation in the melanotic variant, the sole evidence that suggests the diagnosis prior to microscopic examination. Clinical exclusion of metastasis melanoma as a possibility is obligatory. METHODS: We reviewed clinical, imagenologic, endoscopic, and anatomopathological aspects of an ulcerovegetant neoplasm on the esophago-gastric junction, surgically resected, in a 65 years-old man with progressive dysphagia, who was without tumoral relapse during 18 months after surgery. RESULTS: The tumoral mass was an anaplastic cell tumor with very scant melanic pigmentation and diffuses stain for HMB-45 antigen and S100 protein, considering it to be a primary malignant melanoma. The neighboring mucous membrane showed a typical Barrett's esophagus and melanocytic hyperplasia. CONCLUSIONS: 1) Endoscopy may suggest the possibility of esophagus melanoma when there is a vegetate, non-obstructive, pigmented tumor. 2) Immunohistochemistry confirms the entity if HMB-45 antigen and S100 protein are detected in the tumoral cells, while the negative results for keratin and leukocytic common antigen (LCA) eliminate carcinoma and lymphoma as possible diagnoses. 3) In our case, the presence of Barrett's esophagus is exceptional, because it has not been described previously in the literature reviewed.

Stromal tumor of the gallbladder with phenotype of interstitial cells of Cajal: a previously unrecognized neoplasm.

We report a small, well-demarcated stromal tumor of the gallbladder in a 69-year-old woman. The tumor and associated cholelithiasis led to chronic cholecystitis symptoms. The wall of the gallbladder contained a 2.4-cm hypocellular nodule composed of bland spindle-shaped cells that were immunoreactive for vimentin, CD34, and CD117. With the latter antibody, which stains interstitial cells of Cajal (ICC), the neoplastic cells appear fusiform with elongated bipolar projections or dendritic-like cytoplasmic projections. The gallbladder wall adjacent to the tumor contained numerous CD117-positive cells in close contact with the normal smooth muscle cells, whereas two of 10 gallbladders with minimal chronic cholecystitis showed only a few CD117-positive cells. These findings provide evidence that this stromal tumor of the gallbladder shows ICC differentiation similar to some stromal tumors of the gut. The presence of numerous ICC in the uninvolved gallbladder wall suggests that this tumor might have evolved through hyperplasia of ICC.

Atypical angiomyolipoma of the kidney: a distinct morphologic variant that is easily confused with a variety of malignant neoplasms.

BACKGROUND: The purpose of this study was to fully characterize and emphasize the salient features of an unusual variant of angiomyolipoma that the authors believe has been underrecognized. METHODS: Five cases of atypical angiomyolipoma (AAML) of the kidney, two of which were reported previously, were retrieved from the consultation files of one of the authors. In one patient a small extrarenal tumor was examined in addition to the primary renal tumor. The histopathologic features of all six tumors, the immunohistochemical findings of five tumors (including the extrarenal tumor), and the ultrastructure of three tumors were analyzed. Clinical follow-up was obtained for all patients. RESULTS: Two tumors occurred in children and presented as large masses (> or = 15 cm), and 2 tumors were small (< 5 cm) and affected middle-aged adults; the remaining tumor, of intermediate size (6 cm), occurred in an adolescent. One child with tuberous sclerosis also had a small (2 cm) extrarenal lesion. All tumors were circumscribed and had a red-brown cut surface. The largest tumors showed areas of hemorrhage and necrosis. The tumors were highly cellular and composed of various types of multinucleated and mononuclear cells. The most distinguishing of these, and virtually pathognomonic of this entity, were huge cells with abnormal strap-like and ameboid configurations having copious eosinophilic hyaline cytoplasm and myriad nuclei disposed peripherally in a ring-like fashion. Ganglion-like cells, polygonal cells, and spindle cells also were observed. For the most part, all cell types shared the same nuclear features, and except for one tumor, mitoses were negligible. The cells displayed a perivascular arrangement, and grew as loosely organized sheets oriented around abnormally dilated vascular channels or in a hemangiopericytic pattern; glomeruloid vessels were variably present. Notably, adipose tissue was inconspicuous. The tumors stained positive for HMB-45 protein, smooth muscle specific actin, and muscle specific actin antibodies, with a tendency for immunoreactivity to segregate along with individual cell phenotypes. Immunoperoxidase stains also disclosed a prominent and consistent intratumoral histiocytic component and a T-cell lymphoid infiltrate. Ultrastructurally, the tumor cells were replete with organelles showing highly electron-dense granules. All patients underwent radical nephrectomy; three patients with significant follow-up remain free of disease. CONCLUSIONS: AAML exhibits unusual but distinctive "pseudomalignant" histomorphologic features that facilitate its recognition, and a singular immunohistochemical profile that allows diagnostic confirmation. It occurs both sporadically and in association with tuberous sclerosis, affects both the adult and pediatric populations, and has shown an indolent behavior. AAML attests to the biologic and morphologic diversity that characterizes tuberous sclerosis hamartomata in general, and to the plasticity of the yet unclarified precursor of angiomyolipoma in particular.

Opportunistic infections in pediatric HIV infection: a study of 74 autopsy cases from Latin America. The Latin American AIDS Pathology Study Group.

The present report describes opportunistic infections found at 74 autopsies of pediatric HIV/AIDS patients performed at several hospitals in Latin American countries. Fungal infections were the most common (53 cases), Candida sp. (39.18%) and Pneumocystis carinii (20.27%) being the most frequently recognized. Other fungal diseases included histoplasmosis, aspergillosis, and cryptococcosis. Viral infections were present in 31 cases, 38.7% being due to cytomegalovirus. Other viruses recognized included herpes simplex and adenovirus. Additional opportunistic infections were due to Mycobacterium avium-intracellulare, toxoplasmosis, and tuberculosis. Nonspecific bacterial bronchopneumonia was present in 11 cases. Cytomegalovirus and P. carinii coinfection was the most common association found. In this series patients died at a younger age (72% at or younger than 1 year old) and there was a slightly higher number of cases of histoplasmosis and brain toxoplasmosis than in other previously published series of infants and children.

[Lymphoblastic lymphoma in children. Poor response in advanced disease with chemotherapy for non-Hodgkin's lymphoma]. / Linfoma linfoblástico en niños. Respuesta pobre en enfermedad avanzada con quimioterapia de linfoma no Hodgkin.

Fifty three pediatric patients with the histopathological diagnosis of lymphoblastic lymphoma (LL) were studied in a retrospective analysis during a 14 year period. Their age ranged from 1 to 16 years with a median of 7 years. Clinical staging was performed according to Murphy's system. There was one child in stage I (2%), 11 in stage II (21%), 14 stage III (26%) and 27 stage IV (51%). Patients in stage IV, 21 (78%) had initial bone marrow involvement, 4 (15%) central nervous system (CNS) infiltration and 2 (7%) simultaneous infiltration to the bone marrow and the CNS. The chemotherapy program consisted of induction, consolidation and maintenance with CNS prophylaxis. The whole program lasted 36 months. Out of 53 patients there were only 45 evaluable for treatment analysis response. A total of 14 (31%) are alive and in a continuous complete remission, with a median duration of remission of 66 months, 8 (18%) children abandoned treatment with a median duration of remission of 10 months. Twenty three patients (51%) are dead. The actuarial survival at 11 year is of 39% +/- 11% with a median remission rate for the whole group of 11.8 months. No patient in complete remission for more than 24 months has relapsed. We conclude that our chemotherapy program is more than adequate for early stages, but for advanced disease it has been a failure. There is a need to modify the chemotherapy program using a very similar protocol as the one used in high risk childhood acute lymphoblastic leukemia.

[AIDS in children. Experience at the National Institute of Pediatrics]. / Síndrome de inmunodeficiencia adquirida en niños. Experiencia en el Instituto Nacional de Pediatría.

We describe retrospectively the experience with 44 cases of AIDS from January 1987 to October 1991 at the Instituto Nacional de Pediatria, a tertiary care children hospital in Mexico City. All patients with 2 ELISA and a positive Western Blot test were included. Thirty three patients were infected perinatally (75%) and 11 through blood transfusion (25%). Fourty one patients belonged to the P2 classification of the Centers for Disease Control. Chronic diarrhea (77%), lymphadenopathy (75%), hepatomegaly/splenomegaly (70%) and oral candidiasis (61%) were the most common clinical findings. Twenty patients died (45.4%). No statistical relation were found between survival rate and the way of transmission and age at onset. Autopsy was performed in 14 patients and revealed a sharp decrease of lymphoid tissue at all levels with severe thymic atrophy.

[Nephropathy in Schönlein-Henoch purpura]. / Nefropatía en la púrpura de Henoch Schonlein.

Over one hundred patients diagnosed with vascular purpura at the National Institute of Pediatrics between 1979 and 1988 were retrospectively studied. Frequency was similar for both sexes. 82% were between the ages of six months and 11 years old. The extrarenal clinical manifestations were: petechias in 98%; abdominal pain 78% arthralgias 45%; melena 39%; and arthritis in 19% of the cases, 49 patients had nephropathy of different degrees and they did differently, 32 had hematuria with or without proteinuria within a nephrotic range, seven suffered from a nephrotic syndrome, one with a nephritic syndrome and nine others had a combination of two or three syndromes (nephritic/nephrotic/renal failure) with an unfavorable evolution towards terminal renal failure in eight of them; on the other hand, this was not seen in the remaining patients. Thirteen renal biopsies were taken from patients with more severe clinical manifestations, finding in them mesangial proliferation or endo- and extracapillary proliferation. These findings suggest that the initial clinical presentation of the illness allows for the prediction of the future.

[Hemangioendothelioma of the pancreas and choledochus, as a cause of cholestatic neonatal and Kasabach-Merrit syndromes]. / Hemangioendotelioma del páncreas y colédoco, como causa de síndromes colestásico neonatal y de Kasabach-Merrit.

Vascular congenital abnormalities are common in children and are often seen in skin and soft tissues. They are rarely observed in internal organs. They may be found singly or in a multiple fashion. The liver is the most frequently affected organ by this disease. The most common histological variety is the hemangioendothelioma. This is a rare neoplasm of the pancreas. The case of a six month old boy with a pancreatic head hemangioendothelioma, associated with thrombocytopenia and digestive track bleeding is presented. The case is clinically interesting due to the vascular malformation and its location. These in turn caused obstructive neonatal jaundice and very severe liver lesions which contributed to the child's death. Paradoxically, the neoplasm is not considered malignant and the secondarily produced liver lesions could have been prevented if the patient would have been diagnosed correctly and at an earlier stage. Hemangioendothelioma; Kasabach-Merrit syndrome; neonatal cholestatic syndrome.

Subcutaneous phycomycosis caused by Basidiobolus haptosporus: a clinicopathologic and mycologic study in a child.

The clinical, histopathologic, and mycologic aspects of a case of subcutaneous phycomycosis caused by Basidiobolus haptosporus in a 3-year-old boy are reported. This is the first documented case from Central and North America. Oral potassium iodide and trimethoprim-sulfamethoxazole gave excellent therapeutic results.