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Introduction

Cervical cancer is the fourth most common cancer in women, with around 660,000 new cases and around 350,000 deaths reported in 2022 according to the World Health Organization. In 2022, around 10,000 cases of cervical cancer were diagnosed in Japan, and approximately 3,000 patients died of the disease (1). Cervical cancer is caused by infection with HPV. The most common type of cervical cancer is SCC, and LELC is one of its subtypes. LELC tends to occur at a younger age and has a better prognosis than conventional cervical SCC. Cervical LELC shows a similar morphology to that of nasopharyngeal LELC. Some reports have suggested that LELC is associated with EBV and/or HPV (2,3). LELC has a distinct geographic distribution, and EBV has been suggested as a causative factor for LELC, especially in Asian women. There is limited evidence suggesting that EBV acts as the main factor in cervical cancer in Caucasians (2-4). The presence of HPV has been studied in several cases, but its role in the development of cervical LELC is unclear, and few studies have described the cytopathological findings of LELC. In this paper, we report a case of cervical LELC, with an emphasis on the cytological findings.

Case report

Clinical course

A Japanese woman (gravida 2, para 2) in her 40s was diagnosed with HSIL based on cervical cytology at a local clinic. Thereafter, a cervical biopsy revealed HSIL/CIN2-3. She was then referred to Tokyo Women's Medical University Hospital (Tokyo, Japan) for further examination and treatment in August 2021. She had tested positive for high-risk HPV (Hybrid capture Ⅱ, QIAGEN) 52 months earlier, but her medical and family histories were unremarkable. She was diagnosed with HSIL based on a brush cervical cytological examination conducted at our hospital. An HPV genotyping test (Mebgen™ HPV kit, MBL) was negative. A punched-out cervical biopsy revealed non-keratinizing SCC. Pelvic magnetic resonance imaging (MRI) revealed small cysts in the cervix, which were suspected to be nabothian cysts (Fig. 1). Otherwise, no obvious mass was identified in the cervix. Uterine fibroids were found in the posterior wall of the uterine body. Cervical conization was performed, and the histopathological diagnosis was LELC, uterine cervical cancer stage pTⅠB1, according to the 2008 International Federation of Gynecology and Obstetrics (FIGO) guidelines. Laparoscopic radical hysterectomy and bilateral oophorectomy were performed, but there were no residual tumors in the surgical specimens. Three years after the operation, the patient is under follow-up without recurrence or metastasis.

Figure 1 MRI findings of LELC T2-weighted pelvic magnetic resonance sagittal imaging revealed small cysts scattered in the cervix, which were suspected to be nabothian cysts. Otherwise, no obvious masses were identified in the cervix, and uterine fibroids were found in the muscle layer of the posterior wall of the uterine body.

Cytological findings of the uterine cervix (Fig. 2)

The preoperative cytology performed at our hospital was retrospectively reviewed. Atypical squamous cells with orange G-philic cytoplasm were seen, in addition to atypical cells that were indicative of CIN. Clumps of atypical cells with thickened cytoplasm and a metaplastic appearance were also observed. These atypical cells had ill-defined borders. Their nuclei were oval and irregular in shape, exhibiting a slightly increased amount of fine granular chromatin, thickened nuclear edges, and prominent nucleoli. Numerous lymphocytes were seen, along with neutrophils, surrounding the clumps of atypical cells.

Histopathological findings of the uterine cervix (Fig. 3)

Atypical cells with a high nucleocytoplasmic ratio formed weakly connected nests, which exhibited infiltrative growth and were accompanied by marked lymphocytic infiltration. Undifferentiated cancer cells had spread from the mucosa to the muscular layer, which also contained lymphocytes. The lesion extended 3 mm deep and 10 mm wide. Immunohistochemical staining showed that the tumor cells were positive for CK (clone AE1/AE3) and p63 but negative for LMP1 and p16. Additionally, in situ hybridization for EBER failed to reveal positive findings. The antibodies and probes used in this case are shown in Table I.

Table I Antibodies and the EBER probe used in this study.

Table I

Antibodies and the EBER probe used in this study.

Antibody raised against	Clone	Vender	Catalog number	Dilution	Process of immunohistochemical staining
p16	E6H4	Roche	518636005	RTU	ULTRA CC1, 64 min, 100˚C
p63	4A4	Bio SB	BSB 3605	1:100	ULTRA CC1, 64 min, 100˚C
CK	AE1/AE3	CellMaque	313-16-RUO	1:400	Protease, 8 min
LMP1	CS1-4	Roche	05267501001	RTU	ULTRA CC1, 64 min, 100˚C
EBER		Roche	800-2842	RTU	According to manufacturer's protocol

[i] RTU, ready to use; ULTRA CC1, ULTRA Cell Conditioning Solution (Roche, Germany); CK, cytokeratin; LMP1, latent membrane protein 1; EBER, Epstein-Barr Virus Early RNA.

Discussion

LELC is a rare histological type of cervical SCC, with no more than 10 case reports per year in Japan. LELC may be associated with EBV and HPV (2,3), and it has previously been identified at several anatomical sites other than the cervix, including the nasopharynx and lungs (5-13). However, case reports on the contributions of EBV and HPV to cervical LELC are limited. Moreover, very few papers have reported the cytopathological findings of LELC.

Herein, we report a novel case of LELC, along with its cytological findings. The cervical cytological specimen from this case showed cells with unclear borders, round nuclei, mildly increased amounts of chromatin, and clear nucleoli. Furthermore, a small number of lymphocytes and atypical squamous epithelial cells with orange G-philic cytoplasm were observed. There have only been a few reports on the cytological findings of cervical LELC. Reich et al reported that large tumor cells, inflammatory cells, round or oval nuclei, 1 or 2 distinct nucleoli, finely granular cytoplasm, chromatin nuclear border condensation, unclear cell borders, and the absence of keratinocytes, koilocytosis, and glandular structures are characteristics of cervical LELC (14). From a review of cervical smears, Rathore et al found that the tumor cell clusters had an abundant lymphoid background (15). The cytological findings of our case were consistent with these reports; specifically, numerous neutrophils were observed in addition to lymphocytes. A high nucleocytoplasmic ratio, prominent nucleoli, indistinct cell borders, and lymphocyte accumulation are important findings for distinguishing LELC from other tumors, including conventional SCC. Histopathologically, the background shows severe lymphocytic infiltration, showing tumor cells with large irregular nuclei infiltrating and proliferating. The present case involved atypical cells with a high nucleocytoplasmic ratio and weakly connected nests, which exhibited infiltrative growth, accompanied by marked lymphocytic infiltration. This case was diagnosed positive for CK (AE1/AE3) and p63 and negative for p16, LMP1, EBER. Reports on the immunohistochemical and molecular genetic characteristics of LELC are rare.

Previous reports on LELC of the uterine cervix are reviewed in Table SI. Tseng et al reported that 73.3% (11/15) of Asian women with cervical LELC were positive for EBV antibodies (2). Although a few reports of EBV have been associated with the pathogenesis of cervical LELC in Asian women, some reported cases of LELC did not involve EBV antibody positivity (3,16-21). Furthermore, there have been reports of EBV positivity from Spain (22). There have also been positive cases of HPV throughout the world (2,3,23-26), but the periods of positivity were not clarified. Our case involved a LELC patient who had previously exhibited a positive result in a high-risk HPV test, but the preoperative HPV genotyping test was negative. This is reasonable because less than half of HPV infections persist after 6 months (27). However, it is unclear how the presence of HPV positively relates to the onset of LELC.

The treatment of cervical LELC follows that of cervical SCC; operations, radiotherapy, concurrent chemo-radiotherapy, chemotherapy, and other drug therapies are selected depending on the progression of cancer and the pathological histological type. Although the number of cervical LELC cases is small, the prognosis is generally better than that for cervical SCC. It is assumed that EBV and HPV play important roles as causative factors, but the pathogenesis of LELC remains unclear, and the molecular genetic characteristics of LELC as a rare cervical malignant tumor have not been explained. In recent years, the association of LELC with deficient mismatch repair (dMMR) and programmed death-ligand 1(PD-L1) has been reported (28,29), and eventually, the pathology of LELC will likely be elucidated.

In summary, we experienced a case of cervical LELC, a rare type of SCC. As characteristic cervical cytological findings, atypical cells with unclear boundaries and round nuclei containing prominent nucleoli and coarse granular chromatin were observed, as well as numerous neutrophils and lymphocytes. Ultimately, the pathology of cervical LELC, such as the association with dMMR and PD-L1, may be clarified by molecular profiling techniques.

Supplementary Material

Literature review of uterine cervical lymphoepithelioma-like carcinoma.

Acknowledgements

Not applicable.

Funding

Funding: No funding was received.

Availability of data and materials

All data generated or analyzed during this study are included in this article.

Authors' contributions

YA, AN, KO, and TT collaborated on the conception and design of the study. KO, TY, and YN pathologically diagnosed uterine cervix lesions. YA obtained the data and wrote the manuscript. AN and YN provided clinical advice. YA, AN and KO confirm the authenticity of all the raw data. TK, YH, TM and YN analyzed the data and reviewed the manuscript. All authors were involved in the preparation of the manuscript, read and approved the final manuscript.

Ethics approval and consent to participate

Not applicable.

Patient consent for publication

Written informed consent for publication of clinical details was obtained from the patient.

Competing interests

The authors declare that they have no competing interests.

References