Stratified mucin producing intraepithelial lesion

Cervical Stratified Mucin-Producing Intraepithelial Lesion: A Systematic Review of Diagnosis and Management

OBJECTIVES

The aims of the study were to synthesize reported associations of stratified mucin-producing intraepithelial lesion (SMILE) of the cervix with other dysplasia lesions and immunohistochemical (IHC) stains, compare expected patterns of IHC staining to other lesions in the differential diagnosis, and assess follow-up pathology.

METHODS

This systematic review includes all case reports and case series of cervical lesions consistent with SMILE based on the histologic diagnosis described in the original case series. MEDLINE, EMBASE, and Cochrane Database were searched through June 2019. Immunohistochemical analysis, concurrent lesions, and pathology on follow-up were compiled for comparison. Weighted averages of concurrent lesions were calculated.

RESULTS

Nine case reports and case series were included, published between 2000 and 2019. Of 9 studies, 6 and 5 studies reported strong, diffuse staining of p16 and increased expression of Ki-67, respectively. Stratified mucin-producing intraepithelial lesion is associated with human papillomavirus, especially type 18. The weighted average risk of concurrent high-grade squamous intraepithelial lesion was 79% (range = 33%-93%), adenocarcinoma in situ 39% (2.9%-92%), adenocarcinoma 5% (1%-25%), and squamous cell carcinoma 6% (0%-11%). Patients underwent follow-up ranging from repeat Pap to radical hysterectomy, with pathology on follow-up infrequently and irregularly reported.

CONCLUSIONS

Stratified mucin-producing intraepithelial lesion is a rare lesion with a paucity of research on necessary cytology and IHC stains for diagnosis, but p16 and Ki-67 IHC stains can be performed to rule out benign lesions. The lesion is associated with high risk of concurrent high-grade squamous intraepithelial lesion, adenocarcinoma in situ, and invasive carcinoma, but studies on the risk of pursuing fertility-preserving management are needed.

Stratified Mucin-Producing Intraepithelial Lesion of the Cervix: Subtle Features Not to Be Missed

OBJECTIVES

Stratified mucin-producing intraepithelial lesion (SMILE) is an uncommon premalignant lesion of the uterine cervix. A detailed examination of preinvasive SMILE cases including a comparison of the cytologic features with usual-type adenocarcinoma in situ (AIS) and human papillomavirus (HPV) genotyping was performed.

STUDY DESIGN

Excisions and preceding Papanicolaou (Pap) tests were retrieved from the files of 2 tertiary care centers. Histologic review estimated the lesional SMILE proportion. Pap tests were reviewed and assessed for architectural, cellular and background features. Cobas® HPV test was performed.

RESULTS

13 cases were identified. Mean/median patient age was 35/33 years (range 23-51 years). Concurrent high-grade squamous intraepithelial lesion was found in 10/13 (77%) and AIS in 8/13 (62%) cases. In 6 cases, SMILE was dominant (≥50%) and represented in 5/6 corresponding Pap tests. Cytology interpretations differed more often in the SMILE-dominant group (p < 0.05). SMILE and AIS had overlapping features. Feathering and prominent nucleoli were absent in SMILE. HPV DNA was detected in all 12 cases tested. HPV 18 was most common (7/12). Excisions with positive/suspicious margins were reported in 5/6 SMILE-dominant versus 3/7 nondominant cases.

CONCLUSION

SMILE is best considered as an AIS variant for cytologic, etiologic and management purposes. Cytologic features overlap with AIS, but are more subtle and easily missed. HPV testing may play a role in facilitating SMILE detection.