High-risk follicular dendritic cell sarcoma of the tonsil mimicking nasopharyngeal carcinoma.

Follicular dendritic cell sarcoma (FDCS) is often misdiagnosed as a carcinoma or malignant lymphoma due to morphological variability. In FDCS application of routine antibody panels without CD21 and CD23 increases the misdiagnosis rate, because the tumor cells often show focal positivity for usual immunohistochemical markers. Our new case showed a distinct picture due to the uncommon tumor architecture, with extensive areas of necrosis and hemorrhage, the presence of nuclear atypia, and an increased mitotic count and Ki-67 index. These features suggest the classification of this tumor in the category of high-risk malignancies, with uncommon features of FDCSs.

Insulinoma diagnosed as drug-refractory epilepsy in an adolescent boy: a case report.

Solitary insulinoma is a rare pancreatic tumor in all age groups with an estimated incidence of 1 in 250 000 persons a year. It is even rarely in childhood and mostly shows benign behavior. Cases with uncertain or malignant biology are extremely rare with less than 30 cases described in the literature. Here we report a case of pediatric insulinoma, the first in our department files in the past 20 years, with rapid clinical course following a clinical misdiagnosis as juvenile myoclonic epilepsy, which was complicated with low glucose level (20 mg/dL) and neuroglycopenia. Our case underlines some unusual features of a pediatric insulinomas presented without past medical and family history, after surgery complicated with mental retardation and recurrent epileptiform episodes. Despite the small tumor size, low Ki67 index/mitotic rate and benign immunophenotype marked by positivity for pro-insulin but negativity for ß-HCG, the diagnosis was concluded as insulinoma of uncertain biological behavior due to vascular tumor invasion in agreement with the 2003 WHO Classification for Pancreatic Endocrine Neoplasms. Besides these features, perineural invasion can differentiate insulinomas of uncertain outcome from benign insulin producing tumors. Pediatric insulinomas may present misleading symptoms of epilepsy in neglected cases coming from poor socioeconomic background. Chronic insufficient blood glucose level might contribute to mental retardation and epilepsiform myoconvulsions to be prevented. Differentiation between insulinoma with benign and uncertain behavior is difficult where histological pattern and tumor immunophenotype are less important than the critical morphological parameters. Life long follow-up including regular control of blood glucose and abdominal status of patients are essential for proper assessment of clinical outcome of pediatric insulinoma.

Secondary involvement of lymph nodes in Kaposi sarcoma.

Kaposi sarcoma is a low-grade neoplasm first described by Moricz Kaposi in 1872. Although many attempts have been made to explain its pathogenesis, its etiology still remains obscure. In this regard, many aspects of the disease's genetic, epidemiological and histopathological backgrounds are even today unclear. We present the case of a 57-year-old male patient, constant HIV negative, with a history of plaque-like lesions on his right foot approximately two years ago. Following surgical removal, a diagnosis of Kaposi sarcoma, plaque stage was settled. One year after, the patient was admitted to the hospital for pain in the right ankle and foot, associated to paresthesis and trophic lesions at this level. Similar lesions developed in the popliteal fossa. Biopsy and subsequent histological and immunohistochemical examination revealed a KS at that level. The most recent hospital admission revealed the appearance of an indolent lymphadenopathy in the groin. Our case represents a rare occurrence of Kaposi sarcoma at a HIV-negative patient, which, after several local recurrences and progressive behavior, produced a lymph node involvement at the groin level. The immunohistochemical assessments have confirmed the diagnosis.

Diagnostic and differential diagnostic criteria of lymphoid neoplasms in bone marrow trephine biopsies: a study of 87 cases.

The aim of this study is to present the diagnostic and differential diagnostic criteria of the bone marrow specimen involved by lymphomas based on the histomorphological immunophenotype features and clonality of the tumor cells, patterns of lymphoproliferation and diagnostic pitfalls. BMB material obtained from the right posterior iliac crest was represented from 87 untreated and treated patients with BM involving malignant lymphoma, stained with Hematoxylin-Eosin, Giemsa, Periodic Acid Schiff and Gömöri's Silver. In order to perform immunohistochemistry examination we used a large antibody panel. B-cell clonality was determined in six cases. We found eight reactive lymphoproliferative responses and 79 lymphoid neoplasms of which 45 were diagnosed as de novo lymphoma, the rest of 34 samples being examined for staging. The predominant lymphoma was CLL (30 cases), over followed by DLBCL (18 cases). The most frequent patterns of involvement were the interstitial (29%) and mixed (15%) ones. In eight cases, we found reactive lymphoid aggregates. The B-cell clonality test showed four monoclonal, one oligoclonal and one polyclonal diseases form. Diagnosis of lymphoma versus reactive aggregate has been based on the combination of a lot of antibodies and involvement pattern. Although investigation of gene rearrangement was necessary for the establishment of the correct diagnosis in only 6.9% of cases, it should be emphasized that it is of great importance in disease monitoring.