Approximately 8 % of uterine leiomyomas (fibroids) occur in the cervix, making these the commonest benign mesenchymal neoplasms at this site. They are usually solitary. Although, if the overlying mucosa is ulcerated benign smooth muscle cells from the lesion may be present in cervical cytology samples, it has not been reported.

The cervix is very rarely the primary site of this aggressive tumour which typically presents in the reproductive years as a polypoid mass developing beneath the cervical surface epithelium associated with vaginal discharge.

The cytological features in a touch smear preparation of a case have been described by Matsuura et al. and consist of loose clusters of short spindle-shaped cells with elongated, scanty cytoplasm, and indistinct cell borders associated with tumour diathesis. The tumour cell nuclei are elongated or oval with a thin nuclear membrane, variable but usually fine chromatin and tend to have macronucleoli which are partly clear. The degree of cellular atypia ranges from mild to severe. Cross striations are rarely identified and without immunocytochemistry to confirm rhabdomyoblastic differentiation, distinction from other malignant mesenchymal neoplasms is difficult [14].

The appearance of this recently described tumour in cervical cytology preparations has not been documented to date, presumably because it arises from subepithelial mesenchyme and rarely causes ulceration of the overlying epithelium [15–17].

Other benign mesenchymal tumours of the cervix, namely haemangioma, schwannoma, neurofibroma, and lipoma are rare and the cytological findings have not to date been documented in conventional or liquid-based cervical cytology preparations.

Primary malignant mesenchymal neoplasms of the cervix are very rare; the most frequently encountered being leiomyosarcoma. Positive cervical cytology is rarely found in association with these tumours and even when abnormal cells are present it may not be possible to give a specific diagnosis. Cytological features suggestive of leiomyosarcoma are the finding of cell clusters or isolated neoplastic cells with oval to elongated, blunt ended nuclei showing fine granular chromatin with small nucleoli and delicate wispy cytoplasm. Stromal sarcoma of the cervix is usually a manifestation of direct spread from an endometrial stromal sarcoma. Features suggestive of endometrial stromal sarcoma are moderate or markedly cellular preparations composed of a mixture of single cells or stromal fragments in which small blood vessels may be identified. The individual tumour cells are spindle-shaped or epithelioid with minimal anisonucleosis and anisocytosis, fine granular chromatin with indistinct nucleoli, and scant to moderate delicate, amphophilic cytoplasm. The background usually includes blood and necrotic debris [18–20].

This tumour is now generally accepted to be a metaplastic carcinoma [21]. In the majority of cases, carcinosarcoma of the cervix represents spread of tumour from the endometrium: in a series of 202 patients with cervical involvement by this tumour only one case was shown to be a primary cervical neoplasm [22].

The detection rate of malignant cells in cervical cytology preparations from histologically proven carcinosarcoma varies between 56 and 70 %. Most reports and series relate to tumours arising in the body of the uterus rather than the cervix. The histological blend of variable proportions of malignant neoplastic epithelial and stromal tissue, including in some cases heterologous elements showing rhabdomyoblastic or chondrosarcomatous differentiation, with undifferentiated small cells and spindle cells may be reflected in the cytological appearance in cervical cytology preparations, although the mesenchymal component is less commonly represented even in tumours with a predominant sarcomatous component, possibly because the latter does not readily exfoliate [23–25]. In a recent series of histologically proven uterine carcinosarcoma, 75 % of SurePath liquid-based cervical samples were originally reported as adenocarcinoma of possible endometrial origin. The cellular arrangement of the neoplastic epithelial cells is similar in conventional smears and liquid-based cytology samples and consists of neoplastic glandular cells in three-dimensional ball-like clusters, irregular clusters, and cohesive clusters or as dispersed individual cells. Tiny clusters of atypical glandular cells are easily overlooked in atrophic samples. Spindle-shaped malignant cells represent the sarcomatous component and these may show pleomorphism and multinucleation but more often resemble fibroblasts or fibroconnective tissue. The differential diagnosis of the sarcomatous component includes a spindle cell component of cervical squamous cell carcinoma. Heterologous elements are rare and are difficult to recognize with certainty in cervical cytology preparations (Fig. 7.3) [26].

To date there have been no specific reports of the cytological appearance of adenofibroma or adenosarcoma in cervical cytology preparations.

Adenomyomas and polypoid adenomyomas of the cervix are rare. They comprise a mixture of benign endocervical glands and stroma composed predominantly of smooth muscle.

Atypical polypoid adenomyoma also rarely arises in the cervix. The glandular component in this entity is indistinguishable from endometrial intraepithelial neoplasia and there are usually conspicuous squamous morules.

The cytological features of both typical and atypical polypoid adenomyoma have been described in conventional and liquid-based cervical cytology preparations. In both cases cervical smears contained spindle-shaped smooth muscle cells, which in conventional smears may present as cohesive fragments with frayed edges revealing spindle cells with bipolar cytoplasmic processes, but whilst in the case of polypoid adenomyoma there were sheets and strips of reactive endocervical cells in an inflammatory background, in the case of atypical polypoid adenomyoma there were tightly packed, crowded clusters of atypical glandular cells [27–29].