Unusual Contaminants: Arthropod in Pap Smear.

A healthy 30-year-old Latin American woman presented at the gynecology outpatient clinic for an annual check-up. Among her clinical antecedents of interest were the following: sex worker and habitual use of vaginal douches and oral contraceptives. No itching, burning, or vaginal discharge was reported. Speculoscopy was found to be within normal limits. A cervicovaginal sample was collected using a wooden spatula and cytobrush, smeared onto a glass slide (conventional cytology), fixed with cytospray, and stained using the Papanicolaou method.

Microscopic examination revealed the presence of a cylindrically-shaped body that was approximately 280 μm long and 90 μm thick [Figure 1]. Under high magnification, it was possible to distinguish between two groups of crowded squamous cells, a well preserved segmented body with several oval, blue-colored structures that were clearly visible at one end. These structures were arranged in parallel lines, and their sizes ranged from 12 to 8 μm. A noninflammatory background was observed.

Figure 1

Cervicovaginal smear. A cylindrical and segmented structure can be observed between two groups of squamous cells (Pap stain ×200). In the higher magnification inset in the top right corner, it is possible to identify a segmented body with a group of small oval structures similar to eggs (Pap stain ×400)

After careful examination, the observed structure was tentatively catalogued as the abdominal fragment of an arthropod, possibly a copepod (Cyclopoida order), a member of a subclass belonging to the subphylum crustacean. This conclusion was reached after noting the following features: a short, cylindrical, segmented body, abdominal segments without appendages, and an egg sac attached to the body (blue oval structures). In gynecological screening cytology, unusual contaminants are occasionally observed on the smears (e.g., microscopic arthropods such as mites and lice). In some cases, these microorganisms may be derived from running tap water, both in cytological samples (intrinsic contamination) and after the staining procedure (extrinsic contamination).

Copepods are a group of microscopic crustaceans found in marine and freshwater habitats.[1] Their bodies are usually short, cylindrical, and segmented. They consist of a head, a thorax, and an abdomen. In many adult female species, the ova appear enclosed inside twin transparent egg sacs attached to the female's genital segment next to the caudal appendages.

Their presence in human stool samples from patients suffering from perirectal abscesses has been reported.[2] Moreover, in some uncommon diseases, such as sparganosis and dracunculiasis, copepods seem to be involved in vector transmission via contaminated drinking water.[34]

To our knowledge, this is the first time that a contaminant with the described characteristics has been described on a cervicovaginal smear.

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Conflicts of interest

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