Utility of Imprint Cytology in Rapid Intra-operative Diagnosis of Head and Neck Lesions in Patients Attending Surgical Clinics at Kenyatta National Hospital.

Abstract

Intraoperative consultation has offered an important service in patient management. There is need for minimal turnaround time in the laboratory assessment of surgical specimens that will aid the surgeon in formulation of immediate decisions regarding the optimal extent of surgery, diagnosis, rapid initiation of ancillary testing, therapeutic protocol and in guiding surgical management of the patient. The delay in obtaining tissue diagnosis leads to unnecessary apprehension among the patients and delay in definitive workup and treatment. Hence there is need for a rapid on-site evaluation of material obtained during the biopsy procedure. Touch Imprint cytology (TIC) is one of the upcoming methods that can be used in the diagnosis of malignant and benign lesions in shorter period though the histopathology remains the gold standard. Aim: The primary goal of our study was to evaluate the role and determine diagnostic accuracy of TIC in the diagnosis of various head and neck lesions and correlate the cytological diagnosis with final histopathological findings. Materials and Method The study was undertaken after approval by the KNH/UoN ethical research committee. A descriptive cross-sectional study was conducted on 139 patients who presented with different lesions of the head and neck at the hospital surgical clinics in the ENT, dental and main surgical theater. Intraoperatively, after obtaining the fresh biopsy specimen and prior to placing them in

fixative, imprint smears were prepared and processed. Cytological findings were then compared with final histopathological diagnosis. Results: With a male to female ratio of 1.2:1; 139 patients presented with different lesions of the head and neck. The cytology diagnosis analysis determined that 66 cases (47.5%) of the diagnosis were benign, 58 cases (41.7%) were malignant, 8 cases (6%) were suspicious for malignancy while 5 cases (3.6%) were non-diagnostic. The histology diagnosis analysis showed that 56.1% of the diagnosis were benign while 43.9% were malignant. overall diagnostic accuracy of TIC in diagnosing malignant lesions was 92.1% with a sensitivity and specificity of 88 and 94.9% respectively. The measure of agreement based on the Cohen’s Kappa analysis showed a Coefficient (k) value of 0.838; which represented an excellent strength of agreement. Conclusion 1. The commonest benign findings were inflammatory conditions and colloid goiter in adults and inflammatory conditions and cystic lesions in children. 2. The commonest neoplastic lesions in adults were metastatic squamous cell carcinoma, nasopharyngeal carcinoma and lymphoma and in children were 2 cases of retinoblastoma and 1 case each for lymphoma and sarcoma. 3. Intraoperative diagnosis of head and neck malignancies can readily be achieved using touch imprint cytology technique as it can easily be availed at the surgical operative site; moreover, it can offer a rapid and accurate diagnosis for further management of the patient. Recommendations 1. Initiate the use of TIC technique in the intraoperative consultation on urgent cases to reduce diagnostic delays and improve patient management. This should be institutionalized as a standard practice without delay as the resource inputs are already available in the hospital. 2. Incorporate immunohistochemistry technique, special stains and flow cytometry during TIC analysis to improve its accuracy, sensitivity and speed since most malignant lesions were metastatic to the lymph nodes and others were inflammatory lesions caused by different infectious agents