Year : 2008 | Volume
: 25 | Issue : 1 | Page : 33--35
Tubal metaplasia of the endocervix
Dushyant Singh Gaur1, Sanjeev Kishore1, Anuradha Kusum1, Neena Chauhan1, Savita Bansal2, Avneet Boparai1,
1 Department of Pathology, Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun - 248 140, Uttarakhand, India
2 Department of Gynaecology and Obstetrics, Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun - 248 140, Uttarakhand, India
Dushyant Singh Gaur
Department of Pathology, Himalayan Institute of Medical Sciences, Jolly Grant, Dehradun - 248 140, Uttarakhand
Metaplasia is a reversible reprogramming of stem cells of the epithelium. Usually, squamous metaplasia is observed in the endocervix. However, less frequently, tubal metaplasia may develop, replacing nonciliated columnar cells by ciliated columnar cells, similar to fallopian tube epithelium. Here we present a case of tubal metaplasia of the endocervical canal. A 40 year-old female presented with postcoital bleeding; her uterus was retroverted, normal-sized and the fornices were free. Erosion was seen around the external os with ulceration. The clinical diagnosis was chronic cervicitis. Cytobrush sampling showed abundant endocervical columnar cells. A distinct morphological variation showing apical ciliary plates with distinct cilia were noticed in many columnar cells. Mucoid, neutrophil-rich secretions were seen in the background but no malignant cells were seen, resulting in a diagnosis of tubal metaplasia of the endocervical epithelium. There was no Trichomonas vaginalis infection. Tubal metaplasia should be identified as a unique benign identity and should not be confused with early endocervical glandular neoplasia of the cervix. Cytobrush technique for endocervical smears helps detect such uncommon metaplastic changes.
|How to cite this article:|
Gaur DS, Kishore S, Kusum A, Chauhan N, Bansal S, Boparai A. Tubal metaplasia of the endocervix.J Cytol 2008;25:33-35
|How to cite this URL:|
Gaur DS, Kishore S, Kusum A, Chauhan N, Bansal S, Boparai A. Tubal metaplasia of the endocervix. J Cytol [serial online] 2008 [cited 2020 Nov 24 ];25:33-35
Available from: https://www.jcytol.org/text.asp?2008/25/1/33/40657
The inner surface of the female genital tract is lined by a continuous layer of epithelium-nonkeratinizing squamous epithelium lining the vagina and ectocervix, transforming at the external os into columnar secretory cells of the endocervical canal, changing to specialized endometrial epithelium lining the uterine cavity at the internal os and continuing as tubal epithelium of the fallopian tubes till the fimbriae. This tubal epithelium consists of three types of cells: ciliated columnar cells, nonciliated secretory cells, and intercalary or peg cells. 
Metaplasia is defined as a reversible adaptive change brought about by a reprogramming of stem cells present in that region, so that the adult cell type present in the site is replaced by another adult cell type of the same germinal layer. This altered proliferation along a new pathway aims to produce cells more suitable to the adverse, altered or stressful environment around the tissue. 
The squamo-columnar junction situated at the external os of the cervix is one site which is highly vulnerable to metaplasia or neoplastic transformation under adverse circumstances, such as chronic infection or trauma. Usually, squamous metaplasia where squamous cells replace the columnar cells of the endocervical canal, is observed. , However, in less common situations, particularly after trauma, tubal metaplasia may develop, replacing endocervical nonciliated columnar epithelial cells by 'ciliated columnar' cells, similar to those seen in fallopian tubes.  Tubal metaplasia is mostly seen in the upper part of the endocervical canal near the internal os, but may also be found in the endocervical glands or the lower endocervical canal. 
Popularity of cytotechniques like cytobrush have helped in sampling and detection of uncommon changes and early dysplastic and neoplastic lesions in the endocervix.  Here we present one case where cervical pap smear showed evidence of tubal metaplasia.
A 40-year-old female presented with complaints of postcoital bleeding; her routine hematological investigations were within the normal range. Urine examination showed the presence of protein in traces and on microscopy, plenty of pus cells, and squamous epithelial cells. On physical examination, the uterus was found to be retroverted and normal-sized; the fornices were free. Per-speculum examination revealed evidence of erosion around the external os with ulceration of the anterior lip of the cervix. A pinkish mucoid discharge tinged with blood was oozing out of the endocervical canal and a clinical diagnosis of chronic cervicitis was made.
Cervico-vaginal smears were prepared using a sterile wooden spatula and cytobrush. Papanicolaou-stained smears showed good cellularity with predominant intermediate squamous cell population admixed with superficial squames and a few parabasal cells. The background showed a thick, mucoid exudate with abundant neutrophils, mixed with few red blood cells, and cell debris [Figure 1]A. Cytobrush-sampled smears showed abundant endocervical columnar cells, lying individually or in small rows and sheets, along with several bare nuclei. On closer examination, a distinct morphological variation was observed where well-defined ciliary plates with distinct cilia arising from them, were noticed at the apical end of many columnar cells, similar to ciliated fallopian tube cells. These cells also had oval nuclei which were larger than those in the nonciliated endocervical cells lying nearby. A couple of narrow cells with elongated dark staining nuclei, similar to the intercalary peg cells of the fallopian tube epithelium, were also observed [Figure 1]B and [Figure 2]. The smears were negative for intraepithelial lesion or malignancy. Thus, a diagnosis of tubal metaplasia of the endocervical epithelium was made. No Trichomonas vaginalis infection, fungal hyphae or spores were seen in the smears. The patient was prescribed treatment for control of the infection and advised follow-up.
Tubal metaplasia of the endocervical epithelium remained largely unknown till advanced cytological techniques such as cytobrush, came into routine practice. , The cytobrush could easily reach the internal os and beyond and collect cytological samples. As tubal metaplasia is most often observed in the uppermost region of the endocervical canal, close to the endometrial cavity, , cytobrush samplings started revealing these uncommon metaplastic cells with well-defined ciliary plates and cilia in large numbers. In addition, occasional intercalary peg cells, all with mostly well-preserved morphological features were seen. 
Endocervical canal cytology is highly variable due to the myriad of possible lesions such as infectious and inflammatory reactions, metaplasia, dysplasia, and true endocervical neoplastic lesions. , Atypical glandular cells on cervical cytology are a problem for clinicians and pathologists alike. Before cytobrush sampling became popular, some such exfoliated cells did appear in cervical smears, but due to degeneration of their morphological features and inadequate experience on the part of cytopathologists to explain their origin,  such cells were labeled as atypical glandular cells of undetermined significance (AGUS). ,
Recognition of tubal metaplasia of the endocervix as a distinct entity holds significance due to the fact that this condition may be confused morphologically with endocervical dysplasia or adenocarcinoma. , No correlation has been found between the presence of tubal metaplasia and the degree of inflammation or trauma to the cervix.  Similarly, no association of tubal metaplasia has been found with any phase of the menstrual cycle or low-grade cervical intraepithelial neoplasia (CIN). However, tubal metaplasia was found to be inversely related to high-grade CIN in glands, presumably due to the replacement of metaplastic cells by neoplastic cells. 
Cilia are characteristically lost when malignant tumors arise in the cervix having tubal metaplasia.  Thus, the detection of cilia in cytological smears on light microscopy, is frequently used to support a benign diagnosis. However, ciliated carcinomas of müllerian duct origin do occur, albeit rarely, and can pose a potential difficulty in its differentiation from tubal metaplasia. 
Clusters of large cells with ample, vacuolated cytoplasm, and vesicular nuclei containing prominent nucleoli, are findings suggestive of endocervical adenocarcinoma.  However, ciliated cells of tubal metaplasia also show nuclei that are larger than accompanying nonciliated secretory cells, and tend to be hyperchromatic.  Thus, demonstration of the presence of two cell types in addition to endocervical secretory cells, i.e. , peg cells (cells with dark and granular cytoplasm and elongated nuclei) and ciliated cells, should be considered as the criteria for a diagnosis of tubal metaplasia. ,, However, it is very often difficult to demonstrate intercalary peg cells in cytological smears.  If ciliated cells are accompanied by small, highly abnormal cells with irregular hyperchromatic nuclei, a strong suspicion of small cell carcinoma of endocervix should be considered.  Experts unanimously support the separation of adenocarcinoma in situ (AIS) from atypical endocervical cells of undetermined significance when sufficient morphological criteria are present.  However, the diagnosis of a precursor lesion to AIS, endocervical glandular dysplasia, is still considered controversial. 
History of postcoital bleeding and heavy neutrophilic inflammatory exudate in the cervical smears might be the triggering factor for tubal metaplasia in the present case. Tubal metaplasia has been observed as an aberrant metaplastic differentitation following injury to the cervix.  Trichomonas or fungal infection was not detected in the present case.
Over the past few years, certain factors have helped cytologists gain necessary experience to confidently assess these new cellular patterns which cause difficulties in differential diagnosis, and investigate such cases in an efficient and cost-effective manner.  These factors include the recognition of atypical metaplastic and potentially neoplastic entities, their cytologic manifestations, and the effects of increased high endocervical sampling.
To conclude, the main significance of recognizing tubal metaplasia in the cervix lies in identifying it as a definite and benign entity, and not confusing it with early endocervical glandular neoplasia, or ciliated carcinomas of müllerian duct origin.
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