Mastering Cytopathology: Practical Tips for Board Preparation

Introduction

Explore key insights and practical knowledge for cytological interpretation and diagnosis, essential for board preparations and clinical practice.

Cytology Lecture Topics

• Dr. Raja, a pathology professor at Loma Linda University, delivered a lecture on cytology with a focus on selected case images from various body sites.

• The lecture emphasized the importance of recognizing common cellular abnormalities and infections, such as trichomonas infection in GYN cytology, and provided detailed descriptions of the key characteristics to look for in these cases.

• The presentation also covered the identification of low-grade and high-grade squamous intraepithelial lesions, as well as cervical adenocarcinoma, emphasizing the distinct cytological features associated with each condition.

• Furthermore, the lecture highlighted the cytological characteristics of squamous cell carcinoma, including its invasive nature and potential differentiating factors on PAP stain.

• The discussion extended to small cell neuroendocrine carcinoma of the cervix, follicular cervicitis, and Hashimoto thyroiditis, offering insights into recognizing these conditions through cytological examination.

• Overall, the lecture aimed to provide trainees with valuable insights into cytological interpretation and diagnosis, offering practical knowledge for their board preparations and clinical practice.

Thyroid Carcinoma and Breast Lesions Cytology

• Lymphoma development can be detected through an abundance of lymphoid cells, making it crucial to conduct ancillary studies such as flow cytometry or do stain for accurate diagnosis.

• Papillary thyroid carcinoma exhibits internal nuclear pseudo-inclusions, pale powdery chromatin, and eccentric nucleoli, along with a characteristic hypochromatic appearance.

• Medullary thyroid carcinoma displays a salt and pepper chromatin pattern, spindling of the nucleus, triangular cells, and amyloid in the background, requiring careful consideration for accurate diagnosis.

• Thyroid fine needle aspirates follow the Bethesda system, allowing for classification of non-diagnostic, benign, atypical, suspicious for malignancy, or malignant cases.

• Breast lesions in cytology include lactational changes, fibroadenoma, phyllodes tumor, ductal carcinoma, lobular carcinoma, and mucinous carcinoma, each with characteristic cellular features and potential diagnostic challenges.

Understanding Cellular Pathology: Key Points

• Granular cell tumor of the breast and other body sites appears oncosidic due to the granularity of the cytoplasm, and S100 stains are necessary for identification.

• Respiratory cytology may reveal Crayola bodies, which are coughed-up ciliated respiratory columnar cells. These are commonly seen in asthmatic patients and may indicate respiratory epithelial damage.

• Eosinophils with charcoal Laden crystals, Cushman spirals, and excess mucus production are common in patients with asthma and chronic bronchitis.

• Pneumocystis infection can be identified in BAL with frothy appearance and cup-shaped organisms highlighted by silver stains, which is a criteria in HIV positive patients.

• Granulomas present with epithelioid histiocytes, carotid nuclei, and mixed inflammatory cells, indicating granulomatous inflammation. Special stains and cultures may be necessary for confirmation.

• Adenocarcinoma exhibits glandular features, prominent nucleoli, increased NC ratio, and evacuation in the cytoplasm. Metastatic adenocarcinoma should consider the possibility of breast, lung, kidney, or thyroid lesions.

• Neuroendocrine tumors can resemble glandular cells with coarse chromatin, eccentric nuclei, and rosetting appearance, often resembling the structure of glandular cells.

• Small cell carcinoma has salt and pepper chromatin, high NC ratio, nuclear molding, and may resemble lymphocytes. It presents with invasive globular groups of cells.

• Lymphoid cells can be recognized by small blue cytoplasmic dots, indicating the presence of lymphoid cells. For lymphoma, a monomorphic population and flower-shaped mitosis are key diagnostic features.

• Mesothelial cells present with two-dimensional appearance, nuclear equidistance, and peripheral lacy skirt, which distinguishes them from other cell types. Stains and multiple tests are necessary for accurate diagnosis.

• Urine cytology may reveal melamed wolinska bodies in ileal conduit urine, indicating degenerating intestinal lining cells, and stains are important for differential diagnosis.

• Seminal vesicle cells in older male patients and clear cell renal cell carcinoma should be identified in urine samples, with stains aiding in accurate differentiation.

• Hepatocellular carcinoma exhibits widened plates, prominent nucleoli, and cellular appearance, presenting challenges for accurate diagnosis without staining and other tests.

• Pancreatic lesions such as pancreatic ductal carcinoma are characterized by increased cell size, irregular nuclear membranes, and grooved nuclei, necessitating further diagnostic procedures for confirmation.

Understanding Cytology in Pathology

• Papillary epithelial neoplasm and solid and papillary epithelial neoplasm are classic examples of pancreatic tumors with distinct appearances. Their unique features help in identification and diagnosis, making them distinguishable from other pancreatic masses.

• Melanoma can exhibit a wide range of appearances, from melanotic to spindle-shaped. It may also feature internuclear inclusions and macronucleoli, producing powdery melanin. The differential diagnosis for melanoma can be challenging due to its diverse presentations.

• Meningioma is recognized for its characteristic whirling pattern and entrapped nuclei. Its appearance can resemble other lesions, making it crucial to differentiate through careful observation and examination of nuclear features.

• Differentiating between oncocytic Hürthle cell neoplasm and Hashimoto’s thyroiditis on thyroid FNA requires a comprehensive approach. Observing the cell morphology, presence of oncocytic cells, and evaluating the background cellular composition and clinical history are essential for accurate diagnosis.

• The presence of internuclear inclusions in papillary thyroid carcinoma has long been attributed to processing artifacts. However, the consistent appearance of cytoplasm invagination between the nucleus and nuclear membrane in these tumors suggests otherwise. Understanding the histological and cytological characteristics is crucial for accurate interpretation and diagnosis.

• The reporting systems in cytology, such as the Bethesda system, Milan system, and others, provide a standardized framework for communicating findings. These systems help pathologists convey the nature of the lesions, their level of suspicion, and recommendations for further evaluation, ensuring clarity in reporting and management decisions.

Thyroid Cytology Adequacy Criteria and Diagnosis

• The adequacy of thyroid cytology depends on the clinical findings, and not just the number of cells.

• Classic nuclear abnormalities and peppery architecture can indicate thyroid carcinoma.

• In some cases, a lower amount of cellularity is needed for diagnosis, such as in patients with a known history of thyroid carcinoma.

• Inflammatory pathology can still be considered adequate for diagnosis, even if there are no associated thyroid follicular cells, based on the clinical history.

• Differentiating reactive mesothelial cells from mesothelioma can be challenging, but clinical history and additional testing can provide clarity.

• Breast cytology is still relevant in cases of benign or malignant conditions, as well as in lactating women with concerning breast masses.

• Processing CSF samples for cytospin techniques can be challenging with low volumes, but additional samples and correlation with flow cytometry findings are important.

• Salivary gland lesions, such as oncocytoma and Warthin tumor, can be distinguished by the presence of lymphocytes and specific cell characteristics.

• Breast cytology, despite being less common, is still relevant in specific clinical contexts, such as benign or malignant conditions, and in cases of lactating women with concerning breast masses.

Conclusion

Enhance your preparation for board exams and clinical practice by mastering the interpretation and diagnosis of cytological findings. Get ready to recognize common cellular abnormalities and infections, and understand the key characteristics to look for in cytopathology cases.

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