A rare case of high-grade intraductal carcinoma of the upper lip: immunohistochemical and genetic analyses

Low-grade intraductal carcinoma in minor salivary glands: A case report and clinical insights

Rationale

Low-grade intraductal carcinoma (LG-IC), is a rare malignant tumour of the salivary glands which has a very good prognosis and must be differentiated from the other types of salivary gland malignant tumours, which have a totally different behaviour and a worse prognosis.

Patient Concerns

A case is presented of a 52-year-old woman who was first diagnosed and treated in another clinic in 2019 for an LG-IC in the left submandibular gland space. Two years later, she was admitted to our department with a new lesion, this time in the upper jaw lip on the left side, which also turned out to be LG-IC.

Diagnosis

Magnetic resonance imaging and positron emission tomography-computed tomography were performed in order to diagnose and adequately stage the disease prior to the therapeutic intervention.

Outcomes

A 6-month follow-up reveals no sign of recurrence.

Takeaway Lessons

Literature on this rare histopathological entity, as well as the differential diagnosis with the other malignant lesions of the salivary glands and the frequency of metastasis, were reviewed.

Salivary Gland Intraductal Carcinoma: How Do 183 Reported Cases Fit Into a Developing Classification

Salivary gland intraductal carcinoma (IDC) is a very uncommon group of neoplasms. Many names, variations in diagnostic criteria, and newly observed molecular findings (including NCOA4 :: RET , TRIM27 :: RET , HRAS point mutations, and PIK3CA pathway alterations) have generated further confusion in being able to recognize and categorize this group of tumors. Different histologic appearances and patterns of growth suggest there is more than one tumor category, with intercalated duct, apocrine, oncocytic, and hybrid features seen. Frankly destructive invasion further complicates the category, as the name "intraductal" would suggest an "in situ" neoplasm. Recent evidence on fusion-positive IDC demonstrates the same molecular underpinnings in both the ductal and the myoepithelial cells, which aids in further separating these tumors. This article summarizes the historical group of 183 neoplasms classified under the umbrella of IDC and highlights the unique histologic, immunohistochemistry, and molecular features that may further guide nomenclature standardization and harmonization.