Zeitschrift für Zytologie und Histologie

The Sheep in Wolf's Clothing: Vegetable and Fruit Particles Mimicking Cells and Microorganisms in Cytology Specimens

Abstract

Sue Chang, Neda A Moatamed, Christina KY, Nikki Salami and Sophia K Apple

Background: Microorganisms and contaminants, including food contaminants, can be difficult to distinguish in various cytologic specimens. Vegetable and fruit contaminants can be found in specimens from the gastrointestinal tract, as in anal Pap smears, or aspirated into the respiratory tract, as in bronchiolar-alveolar lavage. Some of these materials mimic microorganisms, normal human cells, and even malignant cells, making correct diagnosis of the cytology specimen a challenge. A catalogue of the cytologic appearance of these contaminants will increase awareness of these diagnostic stumbling blocks.
Methods: Commonly eaten fruits and vegetables were selected. In each preparation, a small amount of the edible portions of the fruit or uncooked vegetable were ground with mortar and pestle, and smeared onto glass slides. The slides were fixed in 100% alcohol for Papanicolaou (PAP) stain or air-dried for May-Grunswald-Giemsa (MGG) stain.
Results: All vegetable cells contained nuclei, cytoplasm, and cell walls. Fruit cells contained nuclei and cytoplasm, but variably contained cell walls. Many of the deeply stained nuclei resembled overly stained malignant nuclei or dysplastic cells. Vegetable contaminants can resemble anucleated to intermediate squamous cells, respiratory columnar cells, viral inclusions such as cytomegalovirus or Molluscum contagiosum, fungal elements, and even organisms such as nematodes, Stronglyoides, and Toxoplasma. Fruit contaminants can mimic similar infectious parasites or fungal spores, and contribute to a seemingly necrotic background.
Conclusion: The distinctive morphologic pattern of fruit and vegetable cells make identification of these mimickers of pathologic processes possible, and differentiates them from human cells.