Role of FNAC in the Preoperative Diagnosis of Salivary Gland Lesions.

BACKGROUND: The characteristic cytologic features of the common salivary gland lesions have been well-delineated in literature. However, there also exist cytologic pitfalls and overlapping features that make an accurate diagnosis difficult in few cases. The present study was designed to compare the cytologic findings of salivary gland lesions with the histologic diagnoses, in order to assess the sensitivity, specificity and diagnostic accuracy of FNAC, with an emphasis on discordant cases. MATERIALS AND METHODS: Patients with suspected salivary gland enlargements, who were referred for FNAC, were included in this study, which was done over a 3 year period in a medical college hospital. FNAC was performed by using the standard procedure. Smears were stained by using Papanicolaou's and MGG stains. Cytologic diagnosis was compared with histopathologic diagnosis wherever it was available. RESULTS: Eighty eight patients with salivary gland swellings were included in the study. The ages of the patients ranged from 15 to 82 years, with the M:F ratio being 1.6:1. Out of 88 cases, 68 had swellings in parotid gland, 19 had them in submandibular gland and one had them in hard palate. Pleomorphic adenoma was the commonest neoplasm which was seen in our study. Mucoepidermoid carcinoma (MEC) was the only malignant lesion seen in our study. One each of Warthin's tumour (WT) and MEC were overdiagnosed and underdiagnosed respectively, the reason being squamous metaplasia in WT and subtle nature of malignant cells in low-grade MEC. CONCLUSION: WT and MEC can pose problems in cytologicdiagnosis. Sampling errors and interpretational errors can lead todiscordant diagnoses.

Unicentric Mesenteric Castleman's Disease- A Diagnostic Quandary-A Case Report.

Castleman`s Disease (CD) is a rare lymphoproliferative disorder and a mesenteric location is unusual. The unicentric variety is more difficult to diagnose clinically and it requires a histopathological confirmation. The excision biopsy itself will help both in the diagnosis and in planning the treatment. Here, we are presenting a case of unicentric mesenteric Castleman`s disease which we suspected to be lymphoma.

Ameboma of the colon with amebic liver abscess mimicking metastatic colon cancer.

Amebic colitis is common in developing countries, with its variable and non-specific symptoms. Amebomas occur rarely, resulting from the formation of annular granulation tissue, usually in the cecum and in the ascending colon. This report describes the case of a 59-year-old male who presented with abdominal pain. Radiological examination depicted concentric thickening of the cecal wall with mass formation and a cystic lesion in the liver. The endoscopy performed showed a growth in the ascending colon. Biopsy revealed extensive necrosis and inflammatory cells. The patient was referred to this hospital for surgical treatment with a provisional diagnosis of carcinoma of the colon. Peroperatively, a cecal mass was identified. However, suspected secondaries were not seen on the surface of the liver. Histological examination of the right hemicolectomy specimen revealed cecal and ascending colon amebomas. Trophozoites of Entamoeba histolytica were better recognized after periodic acid-Schiff staining. Treatment with Metronidazole for 2 weeks followed by diloxanide furoate for an additional 2 weeks was administered. The liver lesion resolved completely after 8 weeks. Colonic ameboma accompanied by amebic liver abscess may be misdiagnosed as metastatic colon cancer. A high index of suspicion is essential for diagnosis when dealing with colonic masses and liver lesions, especially in the tropics.

Feasibility and safety of longitudinal magnetic resonance imaging in a rodent model with intracortical microwire implants.

The purpose of this communication is to investigate (1) the feasibility of carrying out longitudinal magnetic resonance imaging (MRI) studies in animals with implanted microwire electrodes adapted for MRI compatibility, (2) the effect of MRI studies on the quality of neurophysiological recordings, (3) the use of MRI to study the extent and recovery of tissue damage due to electrode insertion and (4) histological tissue damage due to MRI. There was no evidence of chronic neural damage caused by repeated MRI by any of the measures used nor any statistical difference in the quality of the electrophysiological recordings between animals that had undergone MRI scans and those that had not.

Cytodiagnosis of actinomycetoma.

Mycetoma is a late clinical manifestation of a subcutaneous infection produced by bacteria (actinomycetoma) or fungi (eumycetoma). The distinction between eumycetoma and actinomycetoma in Fine Needle Aspiration Cytology (FNAC) is as accurate as histopathology. A 55 year old man presented with a slow growing swelling on the plantar aspect of the right foot which was present for the last 10 years. A clinical diagnosis of soft tissue tumor was made and FNAC was advised. Smears revealed mixed inflammatory infiltrate and foreign body type of giant cells along with clumps of fibrillar organisms. Gram stain done later demonstrated gram positive thin branching filaments. A diagnosis of actinomycetoma was rendered. Histopathology of the excised specimen confirmed the cytologic diagnosis of actinomycetoma. Mycetoma can be accurately diagnosed by FNAC, which is a simple, inexpensive technique for rapid diagnosis.

Spontaneous rupture of the malarial spleen.

Spontaneous rupture of the spleen is a well-described occurrence in many diseases, being most commonly found in malaria. Exact incidence of this complication is not clear. In this article, we discuss pathology, diagnostic approach and therapeutic options in a patient with malarial splenic rupture. Ruptures of malarial spleens do heal and attempts at splenic lavage/conservative approach should be the aim in their management. Splenectomy should be reserved for those patients with severe rupture or those with continued or recurrent bleeding.

A comparison of neural feature extraction methods for brain-machine interfaces.

Brain-machine interferes (BMIs) have shown promise in augmenting people's control of their surroundings, especially for those suffering from paralysis due to neurological disorders. This paper describes an experiment using the rodent model to explore information available in neural signals recorded from chronically implanted intracortical microelectrode arrays. In offline experiments, a number of neural feature extraction methods were utilized to obtain neural activity vectors (NAVs) describing the activity of the underlying neural population while rats performed a discrimination task. The methods evaluated included standard techniques such as binned spike rates and local field potential spectra as well as more novel approaches including matched-filter energy, raw signal spectra, and an autocorrelation energy measure (AEM) approach. Support vector machines (SVMs) were trained offline to classify left from right going movements by utilizing features contained in the NAVs obtained by the different methods. Each method was evaluated for accuracy and robustness. Results show that most algorithms worked well for decoding neural signals both during and prior to movement, with spectral methods providing the best stability.

Characteristics of stapedius muscle electromyograms elicited by cochlear implant stimulation in the rat.

The electrical stapedius reflex (ESR) threshold, detected by eardrum acoustic impedance change, is strongly correlated with cochlear implant recipients' behavioral comfort levels. However reports suggest acoustic impedance changes are not detectable in 30-40% of patients. The goals of this study were to develop an animal model and investigate the characteristics of the stapedius muscle electromyogram (SEMG) elicited by a cochlear implant, as an alternative measure of ESR activation. Bipolar tungsten micro wire electrodes recorded the SEMG signal from the stapedius muscle of 6 rats. The cochlea was implanted with a multichannel intracochlear electrode that delivered biphasic electrical pulses. Maximum SEMG potentials were 20-500 microV (mean: 174 microV) or 8-42 dB SNR (mean: 24 dB). The dynamic range of the responses that reached saturation were approximately 10 dB, with threshold inversely dependent on pulse-width and electrode separation. The electrical brainstem response (EABR) threshold was 5.6 dB lower than the ESR threshold on average, but the standard deviation was relatively high (2.4 dB), suggesting that these two signals could provide independent information for objective cochlear implant fitting. Post-operative SEMGs were recorded in several animals; including one animal for up to 63 days. The results suggest the overall feasibility of the approach for objective cochlear implant fitting.