Stratified Mucin-Producing Intraepithelial Lesion (SMILE) of the Uterine Cervix: High-Risk HPV Genotype Predominance and p40 Immunophenotype

Two Head and Neck Carcinomas With Squamous and Mucinous Components and Human Papillomavirus Associations: Maxillary Mucoepidermoid Carcinoma ex Sinonasal Schneiderian Papilloma and Tonsillar Invasive Stratified Mucin Producing Carcinoma (ISMC)

Carcinomas of the head-and-neck region with squamous and glandular/mucinous features constitute a heterogeneous group, with a significant minority of tumors showing an human papillomavirus (HPV) association. The differential diagnosis is usually between mucoepidermoid carcinoma (MEC) and adenosquamous carcinoma. We present here two tumors that exemplify both the challenges of diagnostic classification, as well as the complex relationship to HPV: (a) a low risk HPV positive/p16 negative carcinoma that is most consistent with a relatively typical intermediate grade mucoepidermoid type carcinoma with complete MEC phenotype (three cell types), originating from intranasal sinonasal papillomas with exophytic and inverted patterns, and invading surrounding maxillary compartments, and (b) a p16 and keratin 7 (KRT7) positive carcinoma of the right tonsil, characterized by stratified squamous and mucinous cell (mucocyte) features. Whereas the first tumor represents a typical MEC ex-Schneiderian papilloma, the second is morphologically most consistent with the, novel for this anatomic location, diagnosis of "invasive stratified mucin producing carcinoma" (ISMC), pointing to an analogy to similar, high-risk HPV-driven malignancies recently described in the gynecologic (GYN) and genitourinary (GU) areas. Both tumors, despite their mucoepidermoid-like features had no connection to salivary glands and lacked the MAML2 translocation typical of salivary gland MEC, pointing to a mucosal/non-salivary gland origin. Using these two carcinomas as examples, we attempt to address questions related to: (a) the histological distinction between MEC, adenosquamous carcinoma, and ISMC, (b) similarities and differences between these histological entities in mucosal sites versus morphologically similar salivary gland tumors, and (c) the role of HPV in these tumors.

Stratified Mucin-Producing Intraepithelial Lesion of the Cervix in an HPV-16 Positive Woman: A Rare Encounter

BACKGROUND

Cervical cancer is the fourth most common cancer among women globally and has a strong association with Human Papillomavirus (HPV) infection. Stratified mucinproducing intraepithelial lesion (SMILE), a variant of Adenocarcinoma in situ (AIS), is a rare cervical precancer lesion that is often missed or detected incidentally.

CASE PRESENTATION

The present case report briefs the finding of a 39-year-old woman who presented to the gynecological outpatient department with complaints of vaginal discharge for 6-8 months. She had no history of irregular menstrual cycles or postcoital bleeding. Her routine Pap smear revealed atypical squamous cells of undetermined significance (ASCUS) and was positive for HPV-16 type. Her cervical biopsy report revealed AIS and her histopathological report of hysterectomy revealed SMILE, a variant of AIS.

DISCUSSION

The SMILE variant of AIS is a rare cervical precancerous lesion characterized by the morphological overlap of both squamous intraepithelial lesions and AIS. It is often difficult to diagnose on Pap smear and is commonly associated with high-risk HPV infections. The management of SMILE is the same as that for AIS, which is the excisional procedure followed by a hysterectomy if the margins are negative and depending on the fertility desires of the patient, followed by regular follow-up with HPV testing.

CONCLUSION

SMILE is a rare variant of AIS, which is often missed on cytological screening of the cervix. It is commonly associated with high-risk types of HPV. Hence, incorporating HPV testing in the screening of cervical cancer is important and recommended to increase the overall sensitivity of screening for adenocarcinoma lesions.

TP53 Mutation-driven Stratified Mucin-producing Carcinoma Coexisting With Squamous Cell Carcinoma of the Vulva: A Case Study

Associated with high-risk human papillomavirus infection, invasive stratified mucin-producing carcinoma is a recently characterized adenocarcinoma of the cervix. It often occurs in association with adjacent stratified mucin-producing intraepithelial lesion. Differentiated vulvar intraepithelial neoplasia and related invasive squamous cell carcinoma often arise in background vulvar lichen sclerosus with TP53 mutation as the underlying molecular signature. We present a unique case of vulvar invasive stratified mucin-producing carcinoma-like component coexisting with invasive squamous cell carcinoma in a 64-year-old woman. Both neoplastic components were proven TP53 -driven processes arising in the background of differentiated vulvar intraepithelial neoplasia and lichen sclerosus. The invasive stratified mucin-producing carcinoma-like component behaved aggressively in this case, evidenced by the presence of lymphovascular invasion and inguinal lymph node metastasis.