Mastocytosis in children: clinicopathological study based on 35 cases.

Immunohistochemical staining is useful in the diagnosis of bone marrow infiltration in systemic mastocytosis. However, it is not clear if antibody staining may be helpful in the diagnosis of cutaneous mastocytosis (CM). We studied the histological appearance of CM in 35 pediatric patients. Cases were assigned to three basic clinical groups: I--Urticaria pigmentosa (UP, n=29); II--Mastocytomas (n=4); and III--Diffuse Cutaneous Mastocytosis (DCM, n=2). The analysis of clinical information revealed an association between the presence of diarrhea and a higher number of cells/field. Nine doubtful cases, all of them macules, were selected based on the scarcity of mast cells (MC) and the absence or rarity of other inflammatory cells. We compared the number of cells identified in Giemsa and immunohistochemical stains in definite and doubtful cases. The intraclass correlation statistic tested the concordance between each staining method. All 9 dubious cases according to the Giemsa stain had their CM diagnosis confirmed by the immunohistochemistry analysis. The intraclass correlation between Giemsa and c-kit was good (0.7) when the number of MC was high. However, there was no correlation between the mast cells counts in the two different stains in the dubious cases. The immunohistochemistry with c-kit might make CM diagnosis easier, especially in the macular cases, when there is a lower number of MC.

Liver fibrocystic disease and polydactyly: proposal of a new syndrome.

Liver fibrocystic disease (LFCD), characterized by dilatation of the intrahepatic bile ducts and variable degree of fibrosis, can be present alone or as part of many syndromes, such as Bardet-Biedl syndrome (BBS), Meckel syndrome, Jeune asphyxiating thoracic dysplasia, and Fraser-Jequier-Chen syndrome. We report two cases of LFCD and polydactyly with features similar, but not diagnostic of, BBS. Patient 1 was an 18-month-old boy with mental retardation, polydactyly, chronic renal failure, convergent strabismus, and hepatic fibrosis. Patient 2 was a male neonate with LFCD and polydactyly. Their manifestations could not be diagnosed as any of the previous mentioned entities. Difficulties in the early diagnosis of BBS have been previously reported and this could explain the clinical variability and heterogeneity of manifestations at the time of diagnosis. On the other hand, the existence of liver abnormalities in association with BBS has been previously described, but is rare. Our patients' malformations might represent a new entity where autosomal recessive inheritance is probable, but other patterns cannot be ruled out.

Malignant melanoma in children and congenital melanocytic nevi: DNA content and cell cycle analysis by flow cytometry.

Malignant melanoma (MM) in children, although a rare neoplasm, can occur within a preexisting congenital melanocytic nevus (CMN). All the potential risk factors for this phenomenon are not well known, but increases in S phase and G2 + M phase of cell cycle, DNA aneuploidy, and cell cycle abnormalities in precursor lesions might be among the risk factors. Using paraffin-embedded tissue, we performed a retrospective analysis of DNA content, aneuploidy, and cell cycle by flow cytometry. Two groups of patients were analyzed: 28 children with CMN who did not developed MM, and 6 patients who further developed MM. In this second group, three patients had four biopsies done before the appearance of MM and in two patients biopsies were done after the appearance of MM. All CMN not associated with MM exhibited diploid cells only, their S phase was 11.5% (+/- 3.8), and their G2 + M phase was 2.5% (+/- 2.2). Among those patients who developed MM, 3/6 had an S phase > 15.5 and a G2 + M phase > 2.3 prior to the appearance of MM. Two out of six patients had a tetraploid DNA when MM developed and died with a disseminated MM. They had an S phase > 15.5 and their G2 + M phase was > 2.5. We propose that evaluation of DNA content and cell cycle by flow cytometry is a useful method to supplement biopsy findings in children with CMN who have lesions suspicious of developing a MM.

Histopathology of vascular lesions found in Kasabach-Merritt syndrome: review based on 13 cases.

We reviewed the histopathology of 13 cases of Kasabach-Merrit Syndrome (KMS). In 4 (31%) cases the predominant morphology was that of a tufted angioma (TA). Six (46%) cases were Kaposiform hemangioendotheliomas (KHE), and 3 (23%) cases showed an infantile (juvenile) hemangioma only. Immunostaining for CD34 and actin (HHF-35) was helpful in defining these types of hemangiomas. The TA was characterized by a proliferation of endothelial cells positive for CD34 with a minimal component of actin-positive cells. KHE showed a paucity of immunoreactive cells; only the luminal endothelial cells were positive for CD34. In three cases with the morphology of infantile hemangiomas, actin-positive cells outnumbered the CD34-positive cells. Our findings confirm the observation that the underlying vascular lesion in KMS is usually not an infantile hemangioma as was originally thought, but variants of hemangiomas such as TA and KHE (77% of 13 KMS cases). Infantile hemangioma was the phenotypic substrate of KMS in only 3 of 13 cases.

Takayasu's arteritis coexisting with Wegener's granulomatosis in a teenager with renal insufficiency: case report.

A case of Wegener's granulomatosis (WG) coexisting with Takayasu's arteritis (TA) in a 12-year-old girl is presented. She presented with fulminant and severe renal insufficiency due to crescentic glomerulonephritis. At autopsy, aortic lesions of Takayasu's arteritis coexisted with pulmonary and renal findings of WG, and the patient's serum at autopsy had an elevated level of antineutrophil cytoplasmic antibodies (ANCA). Both forms of vasculitis have been thought to be triggered by infectious agents and it is postulated that this occurrence accounts for the coexistence of the two forms of vasculitis in this case.

Diagnostic and therapeutic approach to sialoblastoma: report of a case.

The natural history of a rare parotid tumor, the sialoblastoma (embryoma) is reported. It is a blastematous neoplasm said to recapitulate the epithelial differentiation of a gland at various stages of development. The tumor grew in a period of 5 years (from shortly after birth until it was excised) to a firm asymptomatic mass measuring 5 cm in greatest diameter. With a diagnosis of adenoid cystic carcinoma (a common misdiagnosis), the patient was referred to the reporting institution, where the diagnosis was revised. Five months later, completion parotidectomy for presumed recurrence failed to demonstrate residual tumor. One year later, the patient appears to be free of disease. The authors propose that sialoblastomas should be regarded neither as benign nor malignant, but as one single disease with local infiltrative potential. Based on this concept, sialoblastomas can be treated with early conservative surgery alone, provided that free margins are obtained.

Demonstration of acid-fast bacilli in skin biopsies from indeterminate leprosy cases.

Because the correct diagnosis of indeterminate leprosy (IL) requires the finding of acid-fast bacilli in skin lesions from clinically and histopathologically suggestive cases, it is necessary to develop a reliable method for this purpose. This paper presents a simple procedure, available to every general laboratory, which consists in obtaining 2 suspensions: SI, by mincing and grinding the tissue in phosphate-buffered saline; and SII, after treating SI with NaOH solution and digesting with trypsin. In 22 IL skin biopsies, bacilli were directly observed in only 3 with the Ziehl-Neelsen (ZN) stain; and with the peroxidase-antiperoxidase method it was impossible to differentiate between nonspecific precipitate and true positive reactions. In contrast, 18 positive results from the same 22 samples were obtained when both SI and SII were evaluated with ZN stain. The logarithmic bacterial index was also increased in at least 7 cases.