Is fine needle aspiration cytology a useful diagnostic tool for granular cell tumors? A cytohistological review with emphasis on pitfalls.

BACKGROUND: Granular cell tumors (GCT) formerly known as Abrikossoff tumor or granular cell myoblastoma, are rare neoplasms encountered in the fine needle aspiration (FNA) service. Named because of their highly granular cytoplasm which is invariably positive for the S-100 antibody, the classic GCT is thought to be of neural origin. The cytomorphological features range from highly cellular to scanty cellular smears with dispersed polygonal tumor cells. The cells have abundant eosinophilic granular cytoplasm, eccentric round to oval vesicular nuclei with small inconspicuous nucleoli. The fragility of the cells can result in many stripped nuclei in a granular background. The differential diagnosis occasionally can range from a benign or reactive process to features that are suspicious for malignancy. Some of the concerning cytologic features include necrosis, mitoses and nuclear pleomorphism. METHODS: We identified 6 cases of suspected GCT on cytology within the last 10 years and compared them to their final histologic diagnoses. RESULTS: Four had histologic correlation of GCT including one case that was suspicious for GCT on cytology and called atypical with features concerning for a malignant neoplasm. Of the other two cases where GCT was suspected, one showed breast tissue with fibrocystic changes, and the other was a Hurthle cell adenoma of the thyroid. CONCLUSIONS: These results imply that FNA has utility in the diagnosis of GCT, and should be included in the differential diagnoses when cells with abundant granular cytoplasm are seen on cytology. Careful attention to cytologic atypia, signs of reactive changes, use of immunohistochemistry, and clinical correlation are helpful in arriving at a definite diagnosis on FNA cytology.

Diffuse large B-cell lymphoma arising in a composite lymphoma with biclonality by flow cytometry and one monoclonal band by PCR.

Composite lymphoma (CL) refers to the presence of two or more distinct types of lymphomas in a single organ or tissue. CL is an infrequent finding and may be due to the existence of two genetically related neoplasms, i.e. transformation of a single lymphoma into another lymphoma, or be due to the presence of two clonally unrelated lymphomas. CL composed of more than two lymphomas is even rare. Herein we describe a case of diffuse large B-cell lymphoma (DLBCL) arising in a CL of follicular lymphoma (FL) and small lymphocytic lymphoma (SLL) in an inguinal lymph node of an 85 year old woman. The three lymphomas were morphologically and immunophenotypically distinct while flow cytometry detected two monoclonal B-cell populations. Karyotyping and Polymerase Chain Reaction (PCR) for B-cell clonality each detected a single monoclonal B-cell population. The morphology findings may suggest DLBCL being transformed from FL while Richter transformation from SLL appears to be less likely in our case. Due to the single clone by chromosome study and PCR study, the precise relationships of the three lymphomas are unknown.

Anaerobiospirillum succiniciproducens sepsis in an autopsy patient: A troublesome diagnostic workup.

Anaerobiospirillum succiniciproducens is an uncommon yet potentially lethal gram-negative bacterium typically affecting patients with comorbidities. We report a case of A. succiniciproducens infection in an autopsy patient who had hepatitis C and type 2 diabetes and describe the difficulties in the laboratory identification of this pathogen.

A case of Philadelphia chromosome positive myeloproliferative neoplasm in a pregnant woman with unusual primary myelofibrosis features.

Myeloproliferative neoplasms (MPNs) are traditionally separated into BCR-ABL-positive chronic myeloid leukemia (CML), and BCR-ABL-negative MPNs including primary myelofibrosis (PMF), essential thrombocythemia (ET), and so forth. One of the diagnostic requirements for PMF and ET is the absence of the Philadelphia chromosome, while its presence is almost universally indicative of CML. However, a diagnostic dilemma arises when Philadelphia chromosome-positive MPNs lack the majority of the typical features seen in CML. Some of these classic CML features include basophilIa, marked leukocytosis, neutrophils left-shift with myelocytes bulge, and "dwarf" megakaryocytes. Presented here is a case of a 32-year-old pregnant patient who did not have typical morphologic findings for CML, and yet the Philadelphia chromosome was positive. The patient demonstrated some pathologic features that are commonly presented in PMF that included bone marrow reticulin fibrosis, leukoerythroblastosis, splenomegaly, and increased serum lactate dehydrogenase.

Microarray, gene sequencing, and reverse transcriptase-polymerase chain reaction analyses of a cryptic PML-RARA translocation.

Acute promyelocytic leukemia (APL) is a well-defined subtype of acute myeloid leukemia (AML) specifically characterized by the t(15;17)(q22;q12) translocation. The t(15;17) results in the fusion of the promyelocytic leukemia (PML) and retinoic acid receptor alpha (RARA) genes. Rare cryptic fusions often associated with small genomic insertions can best be detected by reverse transcriptase-polymerase chain reaction (RT-PCR) although conventional chromosomal studies or even fluorescence in situ hybridization (FISH) analyses appear normal. We report here an APL clone with a cryptic PML-RARA fusion that returned negative results by both karyotyping and fluorescence in situ hybridization (FISH), but returned positive results by RT-PCR analysis. A single nucleotide polymorphism (SNP) microarray analysis was used in this case to help resolve the discordance, revealing a 49-kilobase intragenic PML gene duplication. A dual color dual fusion PML-RARA FISH probe set identified a small, extra PML signal in a chromosome other than 15 or 17. Although coinsertion of a RARA sequence could be detected by neither FISH nor array, the RT-PCR positivity is consistent with this fusion "ectopic" to the natural gene loci. The findings highlight the clinical utility of microarray in cases of cryptic PML-RARA fusion.