Gallbladder carcinoma: An attempt of WHO histological classification on fine needle aspiration material

Abstract

Background: Carcinoma of the gallbladder (CaGB) is common in India and its prognosis depends primarily on the extent of the disease and histological type. We aim to study the role of guided fine needle aspiration cytology (FNAC) for diagnosis of CaGB and to evaluate the feasibility of applying world health organization (WHO) classification on fine needle aspiration (FNA) material to predict the outcome of the tumor.

Materials and methods: Retrospective cytomorphologic analysis was performed in all cases of CaGB diagnosed by ultrasound (US) guided FNAC over a period of 2 years. A specific subtype was assigned according to WHO classification based on characteristic cytologic features. These included papillary or acinar arrangement, intra and extracellular mucin, keratin, rosettes and columnar, signet ring, atypical squamous, small, clear, spindle and giant cells. Correlation with histopathology was performed when available.

Results: A total of 541 aspirations with clinical or radiological suspicion of primary CaGB were studied. Of these, 54 aspirates were unsatisfactory. Fifty cases were negative for malignancy. Remaining 437 aspirates were positive for carcinoma. Histopathologic diagnosis was available in 32 cases. Adenocarcinoma was the most frequent diagnosis in 86.7% of cases. Mucinous, signet ring, adenosquamous, squamous, small cell, mixed adenoneuroendocrine and undifferentiated carcinoma including spindle and giant cell subtypes were diagnosed identifying specific features on FNAC. Correlation with histopathology was present in all, but one case giving rise to sensitivity of 96.8%. No post-FNA complications were recorded.

Conclusions: US guided FNAC is a safe and effective method to diagnose CaGB. Although, rare, clinically and prognostically significant variants described in WHO classification can be detected on cytology.

Keywords: Cytomorphology; fine needle aspiration cytology; gallbladder carcinoma; ultrasound; world health organization classification.

Figure 1

(a) Papillary fragments of tumor cells showing minimal cellular and nuclear pleomorphism, papanicolaou (Pap ×100), (b) intestinal type papillary adenocarcinoma showing true papillae with central fibrovascular cores lined by tall columnar cells and rare goblet cells, H and E, ×100, (c) papillae lined by tall columnar cells along with abundant mucus cells in a case of gastric type of papillary adenocarcinoma, H and E, ×200, (d) columnar tumor cells on cytology, Pap ×400

Figure 2

(a) Tumor cells floating in abundant extracellular mucin, May Grunwald Giemsa (MGG) ×100, (b) mucinous carcinoma showing clusters of tumor cells lying in pools of mucin, H and E, ×100, (c) singly lying tumor cells with abundant intracellular mucin pushing the nucleus to the periphery signifying signet ring appearance, papanicolaou ×400, (d) tumor cells showing moderate nuclear pleomorphism and arranged in cohesive fragments, MGG ×200

Figure 3

(a) Squamous differentiation is typified by atypical keratinized cells with dense cytoplasm and pyknotic nuclei in a necrotic background, Papanicolaou (Pap ×400), (b) Tumor cells showing dramatic anisonucleosis and nuclear molding with rosettes representing neuroendocrine differentiation, May Grunwald Giemsa ×200, (c) Tumor cells show hyperchromatic nuclei with salt and pepper nuclear chromatin and molding in a case of small cell carcinoma, Pap ×400, (d) Large markedly pleomorphic tumor giant cells exhibit neutrophilic phagocytosis, Pap ×400

Figure 4

(a) Undifferentiated carcinoma with predominant spindle shaped tumor cells showing marked nuclear pleomorphism and frequent mitoses, H and E, ×200, (b) Giant cell rich type of undifferentiated carcinoma showing numerous bizarre tumor giant cells, H and E, ×400