Cytologic findings in granular cell tumors, with emphasis on the diagnosis of malignant granular cell tumor by fine-needle aspiration biopsy.

BACKGROUND: Granular cell tumors (GCTs) are uncommon tumors of putative schwannian derivation that are rarely malignant. Although recent studies have addressed a histologic correlation with malignant behavior, similar studies have not been done on cytologic material. METHODS: The authors evaluated 3 malignant GCTs and 17 benign GCTs (comprising 17 fine-needle aspiration biopsy samples and 3 samples from direct scrapes) for the following cytologic features: hyperchromasia; coarse chromatin; nuclear-to-cytoplasmic (N/C) ratio; nuclear pleomorphism; and vesicular nuclei with enlarged nucleoli, mitoses, necrosis, and spindle cell morphology. RESULTS: Hyperchromasia, coarse chromatin, increased N/C ratio, nuclear pleomorphism, and vesicular nuclei with enlarged nucleoli and spindle cell morphology were associated the most closely with malignancy when they were present throughout the cytologic sample. All were diffusely present in three of three malignant tumors, except vesicular nuclei and spindle cell morphology, which were present diffusely in two tumors and focally in one tumor. By contrast, although one to five of these features were present focally in 8 of 17 benign GCTs, none was present diffusely in any benign GCTs, with one exception, which had a combination of focal nuclear pleomorphism and hyperchromasia together with diffuse vesicular nuclei, large nucleoli, and coarse chromatin. The N/C ratio in this tumor was not increased, and there were no spindle cells or mitoses. Mitoses were present in 2 of 3 malignant GCTs and absent from all 17 benign GCTs. Necrosis was not seen in any tumors. CONCLUSIONS: Malignant GCTs have characteristic cytologic features that differ from those of benign GCTs. However, morphologic heterogeneity precludes definitive classification of some tumors by cytologic features alone.

Cytologic diagnosis of gastrointestinal stromal tumor with emphasis on the differential diagnosis with leiomyosarcoma.

BACKGROUND: Gastrointestinal stromal tumor (GIST) has only recently been distinguished histologically and immunochemically from morphologically similar neoplasms of the abdomen. METHODS: The authors reviewed 15 cytologic cases of GIST (14 fine-needle aspiration [FNA] specimens and 1 peritoneal fluid specimen) and compared them with 23 cases of leiomyosarcoma (LMS) arising in the abdomen or pelvis (all FNAs). Immunochemistry (IC) was performed on both the cytologic and subsequent tissue specimens if sufficient specimen was available. RESULTS: Cytologic samples of GISTs typically showed irregularly outlined clusters of uniform spindle cells that were spread easily without crush artifact. The cells had wispy cytoplasm with long, delicate, filamentous extensions (13 cases; 87%). A prominent vascular pattern was common (9 cases; 60%); pleomorphism (1 case; 7%) was uncommon. The LMSs showed three-dimensional, tightly cohesive, sharply marginated syncytia of spindle cells, often with nuclear crush artifact. The cytoplasm/stroma had a distinct wiry, refractile appearance (21 cases; 91%); delicate filamentous cytoplasmic extensions (5 cases; 22%) and prominent vessels (3 cases; 13%) were less common. LMSs more commonly exhibited pleomorphism (14 cases; 61%). Epithelioid cytomorphology, mitoses, and necrosis occasionally were observed in both tumor types. IC for c-kit (on cytologic material) was positive in 10 of 10 cases of GIST (usually diffuse and strong) and 2 of 19 cases of LMS (focal). CD34 positivity favored GIST (4 of 9 cases) over LMS (1 of 19 cases). Smooth muscle actin was positive in 20 of 20 LMSs (strong and diffuse) and 6 of 10 GISTs (usually focal). Desmin was positive in 12 of 20 LMSs and was only focally positive in 1 of 11 GISTs. Correlation of IC results was excellent between cytologic and tissue specimens. CONCLUSIONS: Delicate cytoplasmic processes; a prominent vascular pattern; a lack of nuclear pleomorphism; and a c-kit-positive, desmin-negative immunoprofile are characteristic features of GIST and help distinguish these tumors from LMS in cytologic specimens.

Diagnostic utility of calretinin immunohistochemistry in cytologic cell block preparations.

BACKGROUND: Calretinin (CR) is a valuable marker in the immunohistochemical distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in tissue sections. However, there is limited and conflicting data regarding the utility of CR in this differential diagnosis on cytologic material, especially cell block preparations. Also, the possible role of CR in the distinction of papillary serous borderline tumor (SBT) cells from reactive mesothelial cells in peritoneal washings has not been examined. METHODS: Formalin-fixed paraffin-embedded cell block specimens of cytologic fluids, washings, and aspirates with a suspicious or positive cytologic diagnosis and a confirmed diagnosis of MM (29 cases), ACA (39 cases), and SBT (10 cases) were used for CR immunohistochemistry (IHC). RESULTS: Moderate to strong staining in > 50% of tumor cells was noted in 26 of 29 (90%) MMs but in only 3 of 39 (8%) ACAs and 1 of 10 (10%) SBTs. Admixed reactive mesothelial cells (when present) were strongly positive in all fluid specimens, but the staining pattern of benign non-reactive mesothelial cells in washing specimens was less reliable. CONCLUSIONS: CR is both a sensitive and specific marker of reactive and neoplastic mesothelial cells in cytologic cell block preparations and is thus useful in the differential diagnosis of MM and metastatic ACA in malignant effusions. However, CR IHC does not appear to allow definitive identification of SBT in peritoneal washings.

Relaxivity corrected response modulated excitation (RME): a T2-corrected technique achieving specified magnetization patterns from an RF pulse and a time-varying magnetic field.

We have reworked the theory of RF excitation to enable correction for relaxivity while designing response-modulated excitation (RME) to achieve specified magnetization targets. This results in a significant improvement in the ability to achieve a specified target magnetization, especially if excitation time is long or T2 is short. The methods presented may also be used to improve the quality of spatial-spectral pulses as well as localized spectroscopy, real-time imaging, real-time localized velocity, and noninvasive pressure measurement.