How to Diagnose and Treat CD5-Positive Lymphomas Involving the Spleen

Patients with CD5-expressing lymphomas presenting with splenomegaly are frequently diagnosed with chronic lymphocytic leukemia. The most important differential diagnosis is mantle cell lymphoma, both in its classical and leukemic, non-nodal forms, given its prognostic and therapeutic implications. Other small B-cell neoplasms that frequently involve the spleen and occasionally express CD5 include the splenic marginal zone lymphoma, hairy cell leukemia and, rarely, lymphoplasmacytic lymphoma. The frequency of CD5 positivity depends in part on the sensitivity of the detection methods employed. Usually, a combination of morphological, immunophenotypic and molecular findings allows for a precise sub-classification of CD5-positive, low-grade B-cell lymphomas of the spleen. Some of these tumors may display a mixture of small and larger B cells, raising the possibility of more aggressive lymphomas, such as diffuse large B-cell lymphomas (DLBCL). Approximately 5-10% of DLBCL are CD5-positive and some may manifest as primary splenic lesions. When available, the morphology of DLBCL in the splenic tissue is distinctive and a leukemic picture is very rare. In conclusion, the appropriate morphological and clinical context assisted by flow cytometry panels and/or immunohistochemistry allows the differential diagnosis of CD5-positive, non-Hodgkin, B-cell lymphomas involving the spleen.

Indolent CD8-positive T-cell lymphoid proliferation of the ear: a report of two cases

The current classification of primary cutaneous T-cell lymphoma (CTCL) of the World Health Organization (WHO) includes primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma as a provisional entity awaiting cumulative data. Recent reports identify CD3/CD8-positive clonal T-cell lymphoid proliferations arising in the ear and nose that behave indolently and therefore defy currently established subclassification. Here, we report two cases of clonal CD8-positive/granzyme-B-negative T-cell lymphoid proliferations that arose in the ear and behaved indolently. Collectively, these cases suggest that an additional category of cutaneous indolent CD8-positive T-cell lymphoma may be necessary among the existing classification schemes.

M. Squamous cell carcinomatous meningitis

A case of leptomeningeal carcinomatosis due to a poorly differentiated malignancy is presented. Immunohistochemistry was used to characterize it as a squamous cell carcinoma. Squamous cell carcinomas rarely invade the meninges. There are few well-founded guidelines for managing patients with this condition. Prognosis is generally poor. A literature review of this entity is provided.

Auer rod-like inclusions in a low-grade B-cell leukemia

Auer rods define neoplastic blasts of myeloid origin. However, azurophilic, needle-shaped, Auer rod-like inclusions have rarely been reported in the neoplastic cells of patients with B-cell malignancies, including chronic lymphocytic leukemia/small lymphocytic lymphoma. Here, we report a case of low-grade B-cell leukemia most consistent with chronic lymphocytic leukemia/small lymphocytic lymphoma that displayed numerous intracytoplasmic, needle-shaped, azurophilic rods resembling Auer rods. Furthermore, we review the literature on Auer rod-like structures in B-cell neoplasms.

Concurrent diagnoses of Hodgkin lymphoma and biclonal myeloma in the bone marrow

The diagnoses of Hodgkin lymphoma and multiple myeloma have rarely been made simultaneously in the same patient. We present a case of an 82-year-old man who rapidly developed pancytopenia and liver failure with coagulopathy. Serum protein electrophoresis and immunofixation revealed an unequivocal immunoglobulin Gkappa and immunoglobulin Glambda biclonal gammopathy. Bone marrow biopsy showed involvement by classic Hodgkin lymphoma with an inflammatory background including 49% mature plasma cells. Unfortunately, the patient died 14 days after admission. To our knowledge, a case of concurrent Hodgkin lymphoma and biclonal multiple myeloma has not previously been reported. Detection of severe bone marrow plasmacytosis in the background of Hodgkin lymphoma should alert the pathologist to the possibility of collision with a plasma cell neoplasm, warranting a complete diagnostic workup.

Enteropathy-type T-cell Lymphoma After Intestinal Diffuse Large B-cell Lymphoma

A rare case of enteropathy-type T-cell lymphoma (ETL) developed in a 47-year-old Chinese male 6 years after the diagnosis of diffuse large B-cell lymphoma (DLBCL) in the small intestine. The patient initially presented with vague gastrointestinal complaints. Work-up demonstrated an ulcerated mass in the small intestine. Partial resection and histologic examination of the intestine showed a DLBCL, positive for CD20 and Bcl-2, involving the jejunum transmurally. Further staging work-up demonstrated mesenteric and retroperitoneal lymphadenopathy, splenomegaly, and ascites. The patient was treated aggressively with radiotherapy, chemotherapy, and autologous bone marrow transplant, and complete remission was obtained. Six years later, the patient presented with diarrhea and dehydration. Clinical work-up revealed thickening of the small intestinal wall, and biopsies demonstrated ETL based on morphology, immunohistochemistry, and polymerase chain reaction analysis. Celiac disease was diagnosed concurrently. The patient responded to chemotherapy, received allogeneic peripheral blood stem cell transplantation from an HLA-matched sibling donor, and remains in remission. To our best knowledge, this is the first reported case of metachronous ETL and DLBCL. Possible associations between the 2 types of lymphoma are discussed.

Ewing sarcoma family of tumors in unusual sites: confirmation by rt-PCR

Ewing sarcoma family tumors originating in the palate or adrenal gland are extremely rare and may cause difficulty in diagnosis. More common tumors primary to these sites need to be excluded before one arrives at the correct diagnosis. We have recently diagnosed 2 such cases. The 1st case was that of a 24-year-old woman who presented with a swelling in the right side of the hard palate. The 2nd case was diagnosed in a 28-year-old woman who presented with a mass in the right adrenal gland. In both cases, the diagnosis of Ewing sarcoma family of tumors was confirmed by immunohistochemical studies and reverse transcriptase-polymerase chain reaction (RT-PCR). The hard palate case is the 1st and the adrenal gland the 3rd case of Ewing sarcoma family of tumors arising in these sites, in which the diagnosis was confirmed by RT-PCR and/or cytogenetics. Accurate diagnosis of Ewing sarcoma family of tumors is crucial for the management of patients, and when found in such rare locations, diagnosis should be supported by immunohistochemical and/or molecular genetic studies.

The pathology of NK-cell lymphomas and leukemias

Natural killer (NK) cell lymphomas and leukemias are a rare but clinically important group of neoplasms. Most of these tumors are aggressive, with a high rate of mortality. They include extranodal NK/T-cell lymphomas of nasal type and aggressive NK-cell leukemias. Both are Epstein-Barr virus (EBV) associated and show similar epidemiologic features. A closely related entity seen mainly in children is hydroa vacciniforme-like lymphoma, which also is EBV positive. EBV influences the pathophysiology of these tumors, through the induction of cytokines and chemokines. The differential diagnosis of NK-cell malignancies includes fulminant EBV-associated T-cell lymphoproliferative disorder, a condition referred to in the past as fatal infectious mononucleosis. Benign proliferations of NK cells can be seen in association with viral infection. The disease formerly referred to as blastic NK-cell lymphoma is now considered to be a malignancy derived from a dendritic cell precursor.

Aminoacylase 1 is a sphingosine kinase 1-interacting protein

Sphingosine kinase type 1 (SphK1) and its product sphingosine-1-phosphate have been shown to promote cell growth and inhibit apoptosis of tumor cells. In an effort to further understand the regulation of SphK1, we used a yeast two-hybrid screen to find SphK1-interacting proteins. One of these was identified as aminoacylase 1 (Acy1), a metalloenzyme that removes amide-linked acyl groups from amino acids and may play a role in regulating responses to oxidative stress. Both the C-terminal fragment found in the two-hybrid screen and full-length Acy1 co-immunoprecipitate with SphK1. Though both C-terminal and full-length proteins slightly reduce SphK1 activity measured in vitro, the C-terminal fragment inhibits while full-length Acy1 potentiates the effects of SphK1 on proliferation and apoptosis. Interestingly, Acy1 induces redistribution of SphK1 as observed by immunocytochemistry and subcellular fractionation. Collectively, our data suggest that Acy1 physically interacts with SphK1 and may influence its physiological functions.

Sphingosine kinase type 2 is a putative BH3-only protein that induces apoptosis

There are two isoforms of sphingosine kinase (SphK) that catalyze the formation of sphingosine 1-phosphate, a potent sphingolipid mediator. Whereas SphK1 stimulates growth and survival, here we show that SphK2 enhanced apoptosis in diverse cell types and also suppressed cellular proliferation. Apoptosis was preceded by cytochrome c release and activation of caspase-3. SphK2-induced apoptosis was independent of activation of sphingosine 1-phosphate receptors. Sequence analysis revealed that SphK2 contains a 9-amino acid motif similar to that present in BH3-only proteins, a pro-apoptotic subgroup of the Bcl-2 family. As with other BH3-only proteins, co-immunoprecipitation demonstrated that SphK2 interacted with Bcl-xL. Moreover, site-directed mutation of Leu-219, the conserved leucine residue present in all BH3 domains, markedly suppressed SphK2-induced apoptosis. Hence, the apoptotic effect of SphK2 might be because of its putative BH3 domain.

Sphingosine kinase type 1 promotes estrogen-dependent tumorigenesis of breast cancer MCF-7 cells

The sphingolipid metabolite, sphingosine-1-phosphate (S1P), formed by phosphorylation of sphingosine, has been implicated in cell growth, suppression of apoptosis, and angiogenesis. In this study, we have examined the contribution of intracellular S1P to tumorigenesis of breast adenocarcinoma MCF-7 cells. Enforced expression of sphingosine kinase type 1 (SPHK1) increased S1P levels and blocked MCF-7 cell death induced by anti-cancer drugs, sphingosine, and TNF-alpha. SPHK1 also conferred a growth advantage, as determined by proliferation and growth in soft agar, which was estrogen dependent. While both ERK and Akt have been implicated in MCF-7 cell growth, SPHK1 stimulated ERK1/2 but had no effect on Akt. Surprisingly, parental growth of MCF-7 cells was only weakly stimulated by S1P or dihydro-S1P, ligands for the S1P receptors which usually mediate growth effects. When injected into mammary fat pads of ovariectomized nude mice implanted with estrogen pellets, MCF-7/SPHK1 cells formed more and larger tumors than vector transfectants with higher microvessel density in their periphery. Collectively, our results suggest that SPHK1 may play an important role in breast cancer progression by regulating tumor cell growth and survival.