Surreal image of a salivary gland transforming into a flower, representing MASC.

MASC: Unveiling a Rare Salivary Gland Cancer

Jordan Keane in Health & Wellness December 2025 • 4 min read.

"Explore the characteristics, diagnosis, and treatment of mammary analog secretory carcinoma (MASC), an uncommon salivary gland malignancy."

Mammary Analog Secretory Carcinoma (MASC) is an uncommon type of cancer that develops in the salivary glands. It was officially identified in 2010 and what makes MASC unique is a specific genetic change: a fusion between the ETV6 and NTRK3 genes. While rare, understanding MASC is crucial for early detection and effective treatment.

Historically, MASC was often mistaken for other salivary gland tumors due to overlapping features. However, advancements in genetic testing have enabled more accurate diagnoses. This means doctors can now better distinguish MASC from other similar conditions, leading to more tailored treatment plans.

This article will explore the key characteristics of MASC, including how it's diagnosed, its common locations, and typical treatment strategies. We'll also discuss the importance of ongoing research to improve our understanding and management of this rare cancer.

What are the key characteristics of MASC?

Surreal image of a salivary gland transforming into a flower, representing MASC.

MASC often presents as a slow-growing, painless mass in the parotid gland, the largest of the salivary glands located in front of the ear. While MASC can occur at any age, it is most frequently diagnosed in adults between 40 and 60 years old. Because of the vague symptoms and slow growth pattern, diagnosis can sometimes be delayed.

To accurately diagnose MASC, doctors rely on a combination of techniques:

Physical Exam: A thorough examination of the head and neck area to assess the size and location of any mass.
Imaging: Techniques like CT scans or MRI to visualize the tumor and determine its extent.
Biopsy: Removing a small tissue sample for microscopic examination by a pathologist. This is the gold standard for confirming a MASC diagnosis.
Genetic Testing: Identifying the ETV6-NTRK3 gene fusion, a hallmark of MASC.

Microscopically, MASC tumors have a distinctive appearance, resembling secretory carcinoma of the breast – hence the name “mammary analog.” The tumor cells typically form small cysts or tubules and contain a pinkish fluid. The presence of the ETV6-NTRK3 gene fusion confirms the diagnosis, distinguishing MASC from other salivary gland tumors with similar appearances.

The Future of MASC Research

While significant progress has been made in understanding MASC, continued research is essential to improve treatment strategies and outcomes. Areas of focus include identifying new therapies that specifically target the ETV6-NTRK3 fusion protein, as well as developing more effective methods for detecting and managing advanced MASC. With ongoing research and collaboration, we can continue to improve the lives of those affected by this rare cancer.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1001/jamaoto.2018.2936, Alternate LINK

Title: Analysis Of Clinical Features Of Mammary Analog Secretory Carcinoma Using The Surveillance, Epidemiology, And End Results Database

Subject: Otorhinolaryngology

Journal: JAMA Otolaryngology–Head & Neck Surgery

Publisher: American Medical Association (AMA)

Authors: Jennifer L. Anderson, Yarah M. Haidar, William B. Armstrong, Tjoson Tjoa

Published: 2019-01-01

Everything You Need To Know

What exactly is Mammary Analog Secretory Carcinoma (MASC)?

Mammary Analog Secretory Carcinoma (MASC) is a rare form of cancer that originates in the salivary glands. This cancer was officially recognized in 2010. It is characterized by a specific genetic alteration: a fusion between the ETV6 and NTRK3 genes. This genetic fusion is a key identifier for MASC, distinguishing it from other salivary gland tumors. Understanding MASC is critical for early detection and effective treatment.

Where is MASC typically found, and who is most likely to be affected?

The most common location for MASC is the parotid gland, the largest salivary gland situated in front of the ear. MASC is usually diagnosed in adults between the ages of 40 and 60. It often presents as a slow-growing, painless mass. Because symptoms are vague and the growth is slow, diagnosis can sometimes be delayed, underscoring the importance of awareness and thorough examinations when any unusual lumps or masses are discovered in the head and neck region.

What diagnostic methods are used to identify MASC?

To accurately diagnose MASC, doctors use a combination of methods. These include a physical examination to assess any mass, imaging techniques like CT scans or MRI to visualize the tumor, a biopsy to examine a tissue sample under a microscope, and genetic testing to identify the ETV6-NTRK3 gene fusion. Genetic testing is a crucial step in differentiating MASC from other salivary gland tumors due to overlapping features.

How is MASC distinguished under a microscope, and what is its characteristic appearance?

The microscopic appearance of MASC tumors is distinctive, resembling secretory carcinoma of the breast, which gives the tumor its name, Mammary Analog Secretory Carcinoma. The tumor cells form small cysts or tubules and contain a pinkish fluid. The presence of the ETV6-NTRK3 gene fusion confirms the MASC diagnosis, helping to distinguish it from other similar-looking salivary gland tumors.

What is the future of MASC research, and why is it important?

Continued research into MASC is crucial for improving treatment strategies and patient outcomes. Current research focuses on identifying new therapies that specifically target the ETV6-NTRK3 fusion protein, a hallmark of MASC, as well as improving methods for early detection and managing advanced stages of the cancer. Collaboration and ongoing study are vital to advancing the treatment and care of those affected by this rare form of cancer.