Cytomorphology of unusual infectious entities in the Pap test

Abstract

Rare entities in the Pap test, including neoplastic and non-neoplastic conditions, pose challenges due to their infrequent occurrence in the daily practice of cytology. Furthermore, these conditions give rise to important diagnostic pitfalls. Infections such as tuberculosis cervicitis may be erroneously diagnosed as carcinoma, whereas others, such as schistosomiasis, are associated with squamous cell carcinoma. These cases include granuloma inguinale (donovanosis), tuberculosis, coccidioidomycosis, schistosomiasis, taeniasis, and molluscum contagiosum diagnosed in Pap tests. Granuloma inguinale shows histiocytes that contain intracytoplasmic bacteria (Donovan bodies). Tuberculosis is characterized by necrotizing granulomatous inflammation with Langhans-multinucleated giant cells. Coccidioidomycosis may show large intact or ruptured fungal spherules associated with endospores. Schistosoma haematobium is diagnosed by finding characteristic ova with a terminal spine. Molluscum contagiosum is characterized by the appearance of squamous cells with molluscum bodies. This article reviews the cytomorphology of selected rare infections and focuses on their cytomorphology, differential diagnosis, and role of ancillary diagnostic studies.

Keywords: Cytology; GYN cytology; Pap test; cytopathology; infection.

Figure 1

Granuloma inguinale (donovanosis) in a conventional Pap test. Granulomatous inflammation is shown with epithelioid histiocytes and lymphocytes (a). The organisms (Donovan bodies) can be seen in thin-walled intracytoplasmic vacuoles (circle ) (b). (Pap stain, Mag ×200 in a and ×400 in b).

Figure 2

Tuberculosis cervicitis in a conventional Pap test. The cervical smear shown reveals granulomatous inflammation with large aggregates of epithelioid macrophages (a, b) and multinucleated giant cells (c, d) present in a bloody and necrotic background. (Pap stain, Mag ×400)

Figure 3

Coccidioidomycosis in a liquid-based (ThinPrep) Pap test. Large round and tear-shaped fungal spherules are demonstrated with some endospores characteristic for coccioidomycosis. (Pap Stain, Mag ×200 in a and ×400 in b)

Figure 4

Schistosoma haematobium in a conventional Pap test. Several ova can be seen with a terminal spine (circles) that are scattered among numerous inflammatory cells. (Pap stain, Mag ×200 in a and ×400 in b)

Figure 5

Schistosomiasis and squamous cell carcinoma in a conventional Pap test. The smear shows keratinizing squamous cell carcinoma with necrosis (a, b), and associated scattered Schistosoma ova (c, d) on the slide. Note the terminally located spine (d) in the eggs that is characteristic for Schistosoma haematobium. The background is hemorrhagic. (Pap stain, Mag ×400)

Figure 6

Taeniasis (tapeworm infection) in a conventional Pap test. Two Taenia eggs (a, b) can be seen in the background of inflammation. The eggs contain mature larva. (Pap stain, Mag ×200 in a and ×400 in b)

Figure 7

Molluscum-like bodies in a conventional Pap test. The cytology is characterized by the presence of numerous large intracytoplasmic eosinophilic waxy bodies that tend to push the faintly visible host nucleus toward the periphery (a). The background is bloody with a predominance of acute inflammatory cells (c,d). (Pap stain, Mag ×400)