Histiocytic Disorder Mimicking a Brain Tumor: A Report of 2 Rare Cases.

BACKGROUND Histiocytic disorders, a group of disorders with heterogeneous pathogenesis, morphology, and clinical presentation, include Rosai-Dorfman disease, Langerhans cell histiocytosis, and Erdheim-Chester disease. They can mimic primary or metastatic tumors, both clinically and radiologically, when involving the brain. Therefore, it is crucial to present and discuss cases of histiocytic disorder involving the central nervous system (CNS) to provide new information on disease presentation and diagnosis more. In this paper, we present 2 cases of histiocytic lesions involving the brain and mimicking primary brain tumors. CASE REPORT Case 1: A 65-year-old man presented with increasing memory loss, confusion, and depression. CT scans showed an isolated 2.9×2.0×0.6 cm intracranial hypothalamic lesion. Case 2: A 61-year-old woman presented with dizziness and confusion for 3 weeks and headaches for 1 day. MRI showed a single 5.0×4.0×3.3 cm extra-axial, dural-based, avidly enhancing, well-defined lesion along the left parietal convexity causing mass effect upon the underlying brain parenchyma, left atrial effacement, and minimal vasogenic edema. CONCLUSIONS Histiocytic disorders are relatively rare in the CNS compared with other locations and mimic more common entities in the brain, such as glioma or metastatic tumors. Despite its rarity, one should remain aware of the condition and consider it in the differential diagnosis. This article provides a brief review and adds pivotal data to the literature.

γδ T-Cell Acute Lymphoblastic Leukemia/Lymphoma: Discussion of Two Pediatric Cases and Its Distinction from Other Mature γδ T-Cell Malignancies.

Gamma delta (γδ) T-cell antigen receptor (TCR) expression and its related T-cell differentiation are not commonly reported in T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). Here we report two pediatric T-ALL cases and present their clinical features, histology, immunophenotypes, cytogenetics, and molecular diagnostic findings. The first patient is a two-year-old girl with leukocytosis, circulating lymphoblasts, and a cryptic insertion of a short-arm segment at 10p12 into the long-arm segment of 11q23 resulting in an MLL and AF10 fusion transcript, which may be the first reported in γδ T-ALL. She responded to the chemotherapy protocol poorly and had persistent diseases. Following an allogeneic bone marrow transplant, she went into remission. The second patient is an eleven-year-old boy with a normal white cell count, circulating blasts, and a normal karyotype, but without any immature cellular markers by flow cytometric analysis. He responded to the chemotherapy well and achieved a complete remission. These cases demonstrate the diverse phenotypic, cytogenetic, and molecular aspects of γδ T-ALL. Early T-precursor- (ETP-) ALL and their differential diagnosis from other mature γδ T-cell leukemia/lymphomas are also discussed.

Karyopyknotic cytoplasmic inclusions in neutrophils.

Karyopyknotic cytoplasmic inclusions in neutrophils (KPCI) have been previously called "Howell-Jolly" like inclusions and identified in immunosuppressed patients with human immunodeficiency virus (HIV) and in patients with various malignancies who have undergone chemotherapy. Attempts to characterize these inclusions have included the Grocott's methenamine silver (GMS), periodic acid Schiff (PAS), Gram, and Feulgen stains. Previous authors have concluded that these inclusions are of deoxyribonucleic acid (DNA) origin. We present a case describing an additional method to confirm this observation and to document previously undescribed curvilinear forms.

Pharmacodynamic evaluation of temsirolimus in patients with newly diagnosed advanced-stage head and neck squamous cell carcinoma.

BACKGROUND: Activation of the mammalian target of rapamycin (mTOR) pathway in surgical margins of head and neck squamous cell carcinoma (HNSCC) is a predictor of recurrence and patients with minimal residual disease may benefit from adjuvant therapy with temsirolimus, an mTOR inhibitor. METHODS: The effects of 3 weekly doses of 25 mg of temsirolimus on Akt/mTOR pathway biomarkers were evaluated in tumor and peripheral blood mononuclear cells (PBMCs) of patients with HNSCC. Adverse events were assessed. RESULTS: Temsirolimus significantly decreased pS6 and p4E-BP1 in tumors, and pS6 and pAkt in PBMCs (p < .05). There was no significant upregulation of pAkt(Ser(473)) in tumor tissue. Side effects were minimal and reversible. CONCLUSION: Significant inhibition of the mTOR pathway was noted in both tumors and PBMCs of HNSCC with minimal side effects. The mTOR inhibitors can potentially be used as adjuvant therapy for patients with minimal residual disease and PBMCs are potential surrogate markers in this setting.

The role of fluorescence in situ hybridization and polymerase chain reaction in the diagnosis and classification of lymphoproliferative disorders on fine-needle aspiration.

BACKGROUND: Fine-needle aspiration (FNA) has been used in the evaluation of lymphadenopathy for a long time and is highly reliable in the identification of metastatic malignancies. However, the role of FNA in the assessment of new lymphoproliferative disorders continues to be a subject of debate. The objective of the current study was to evaluate the role of molecular cytogenetic studies in FNA diagnoses of lymphoproliferative disorders. METHODS: A retrospective, computer-based search for lymph node FNAs from 2006 to 2007 was performed. Cases with either fluorescence in situ hybridization (FISH) and/or polymerase chain reaction (PCR) studies were subjected to further analysis. RESULTS: In total, 243 lymph node FNAs were performed during the period, including 104 that were positive/suspicious for metastatic malignancies, 16 that were positive/suspicious for lymphomas, 15 that demonstrated atypical lymphoid proliferation, 73 that were reactive, 14 that were deemed granulomas, and 21 that were determined to be nondiagnostic. Molecular analysis included combined FISH/PCR in 4 cases, FISH only in 7 cases, and PCR only in 4 cases. By using multiplex PCR, 6 cases with atypical/negative flow cytometry results were diagnosed as 4 B-cell lymphomas, 1 T-cell lymphoma, and 1 reactive lymph node; and 4 cases that had atypical T cells determined by flow cytometry were diagnosed as reactive. One CD10-negative follicular lymphoma and 2 cases with suspicious flow cytometry results were positive for t(14;18)(q32;q21) by FISH. Forty-five cases had follow-up histology with 3 false-negative findings and no false-positive results. CONCLUSIONS: In this study, multiplex PCR studies for immunoglobulin heavy-chain or T-cell receptor gene rearrangements were useful for demonstrating clonality, and FISH studies were able to detect translocations or gene rearrangements that allowed for the subclassification of B-cell non-Hodgkin lymphomas.

Comparison of FISH and quantitative RT-PCR for the diagnosis and follow-up of BCR-ABL-positive leukemias.

BACKGROUND: For Philadelphia chromosome positive (Ph+) leukemias (chronic myelogenous leukemia [CML], acute lymphoblastic leukemia [ALL], and rare other leukemias), both allogeneic transplantation and treatment with tyrosine kinase inhibitors offer chances of molecular remission (the molecular marker being consistently undetectable). Molecular remission is defined as a reduction in the quantification of BCR-ABL transcripts to an undetectable level by molecular diagnostic methods, and is considered as a surrogate marker for cure or long-term disease control. The molecular diagnostic methods including fluorescence in situ hybridization (FISH) and quantitative reverse transcription-polymerase chain reaction (QRT-PCR) are more sensitive than classical cytogenetic analysis for the detection of BCR-ABL positive cells. QRT-PCR, due to its superior sensitivity, is considered the gold standard for the follow-up of Ph+ leukemias treated with imatinib. AIM: The objective of our study was to compare the diagnostic and clinical usefulness of FISH and QRT-PCR at different timepoints for Ph+ leukemias. PATIENTS AND METHODS: We investigated 23 unselected patients with Ph+ CML (n = 21) or Ph+ ALL (n = 2) at 77 different timepoints in a comparative study with both FISH and QRT-PCR using commercially available reagents in a routine laboratory. RESULTS: Our study demonstrated a good correlation of QRT-PCR with FISH in detecting the BCR-ABL fusion gene among patients with CML or ALL (coefficient of correlation = 0.77493, p < 0.0001, using Spearman's correlation procedure). All newly diagnosed or untreated cases were positive with both methods. Lower coefficients of correlation were found when FISH and QRT-PCR were correlated with the white blood cell count (WBC). An overall concordance of FISH and QRT-PCR (being either negative or positive in both tests) was found in 65 cases (84.4%) and a discrepancy identified in 12 cases (15.6%). CONCLUSIONS: We confirm that QRT-PCR allows precise measurement of low levels of BCR-ABL transcripts and can serve as a sensitive indicator for minimal residual disease. In addition, we demonstrate in most cases a good correlation of QRT-PCR with FISH in detecting the BCR-ABL fusion gene among patients with CML or Ph+ ALL. FISH is not suitable for monitoring minimal residual disease.

Comparative gene expression analysis of a chronic myelogenous leukemia cell line resistant to cyclophosphamide using oligonucleotide arrays and response to tyrosine kinase inhibitors.

Acquired imatinib resistance in chronic myelogenous leukemia (CML) can be the consequence of mutations in the kinase domain of BCR-ABL or increased protein levels. However, as in other malignancies, acquired resistance to cytostatic drugs is a common reason for treatment failure or disease progression. As a model for drug resistance, we developed a CML cell line resistant to cyclophosphamide (CP). Using oligonucleotide arrays, we examined changes in global gene expression. Selected genes were also examined by real-time PCR and flow cytometry. Neither the parent nor the resistant lines had mutations in their ATP binding domain. Filtering genes with a low-base line expression, a total of 239 genes showed significant changes (162 up- and 77 down-regulated) in the resistant clone. Most of the up-regulated genes were associated with metabolism, signal transduction, or encoded enzymes. The gene for aldehyde dehydrogenase 1 was over-expressed more than 2000-fold in the resistant clone. BCR-ABL was expressed in both cell lines to a comparable extent. When exposed to the tyrosine kinase inhibitors imatinib and nilotinib, both lines were sensitive. In conclusion, we found multiple genetic changes in a CML cell line resistant to CP related to metabolism, signal transduction or apoptosis. Despite these changes, the resistant cells retained sensitivity to tyrosine kinase inhibitors.

Pathologic studies useful for the diagnosis and monitoring of plasma cell dyscrasias.

The pathologic diagnosis of multiple myeloma and other plasma cell dyscrasias includes histopathologic examination of a bone marrow aspirate and biopsy and clinical laboratory tests to assess end organ damage and other prognostic information. Plasma cell dyscrasias are characteristically classified and staged based on the results of these pathologic studies in conjunction with other clinical and radiologic parameters. New staging systems such as the International Staging System (ISS) use readily available laboratory tests to stratify prognostic subgroups. The continued introduction of new laboratory assays will help improve our understanding of plasma cell dyscrasias and the therapeutic management of these patients.

Increased transferrin receptor expression following 11q23 deletion as a mechanism of malignant progression in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a common adult leukemia characterized by the accumulation of mature neoplastic B-lymphocytes. Typically, CLL follows an indolent course, with most patients surviving for many years. However, 10-20% of CLL patients carry 11q23 chromosomal deletions and often exhibit a more severe disease course, with earlier onset of symptoms, shortened lymphocyte doubling time, poor response to therapy, and shortened survival. The molecular basis for 11q23 deletions resulting in a poor prognosis is currently poorly understood. The tumor suppressor gene, ataxia-telangiectasia mutated (ATM, 11q22.3-23.1), is considered a likely candidate gene whose loss could result in the poor prognosis associated with 11q23 deletion and is mutated in a significant percentage of CLL cases. Recently, recombinant ATM expression in ATM-deficient cells was found to decrease transferrin receptor (TfR) expression, suggesting that deletion of the chromosomal region carrying ATM results in increased TfR expression. TfR imports iron into cells, an event necessary for DNA synthesis and cell growth. Additionally, rapidly growing malignant cells, including lymphomas and CLL, often express high TfR levels. Based on this, we propose that one molecular mechanism by which 11q23 deletions confer a poor prognosis in CLL is via increased TfR expression secondary to ATM loss, resulting in the increased cellular iron import, and hence increased capacity for malignant growth. Our hypothesis may also partially explain why gallium, an atomically iron-like toxic metal that binds to transferrin and the TfR is incorporated into cells and was previously demonstrated to have anti-tumor activity in patients with lymphomas refractory to other chemotherapeutic treatments.

Fever, chills, and weakness in a 61-year-old man.

A 61-year-old man presented to the emergency department of a community hospital with a 2-week history of fever, chills, and sudden extreme weakness of his right arm and lower extremities. He also had a cough, shortness of breath, nausea, abdominal pain, diarrhea, and myalgia. Though initially alert and cooperative, he quickly became unresponsive. In addition, he had hyponatremia, renal insufficiency, and compromised cardiopulmonary function. He was admitted to the intensive care unit for suspected bacterial infection and was started on broad-spectrum antibiotics. Chest radiograph revealed miliary infiltrates consistent with infectious emboli or metastatic carcinoma. Despite intensive resuscitation, the patient died 36 hours after admission. At autopsy multiple nodular lesions were observed on gross examination of the lungs, perihilar and paratracheal lymph nodes, and liver. Microscopic sections of the lung (Figure 1) and brain (Figures 2 and 3) are shown.