{"id":29518,"date":"2025-08-01T08:53:55","date_gmt":"2025-08-01T13:53:55","guid":{"rendered":"https:\/\/www.aae.org\/specialty\/?p=29518"},"modified":"2025-08-05T13:49:55","modified_gmt":"2025-08-05T18:49:55","slug":"29518-2","status":"publish","type":"post","link":"https:\/\/www.aae.org\/specialty\/29518-2\/","title":{"rendered":"When It\u2019s Not Just Endo: Lessons from a Carcinoma Hiding in Plain Sight"},"content":{"rendered":"

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\nBy Ji Wook Jeong, DDS, MS<\/em><\/p>\n

As endodontists, we are trained to diagnose and differentiate complex orofacial pain and periapical disease with precision. But every so often, a case reminds us that not all radiolucencies are endodontic\u2014and not all toothaches are what they seem.<\/p>\n

This was the case with a 57-year-old male patient who had previous root canal treatments in the teeth #26, #25, and #24 (Fig.1) because his TMD specialist requested root canal treatments before mouth appliance if any risk of pulpal infection. However, the patient continued to suffer persistent, radiating pain. He had no facial swelling or paresthesia, but he did report difficulty swallowing, ear pain, and limited mouth opening. These signs, while subtle in isolation, became more concerning when considered together.<\/p>\n

A periapical radiograph revealed a poorly defined radiolucency from tooth #26 to #24 (Fig.1) and CBCT confirmed a through-and-through lesion (Fig.2A) with external root resorption at multiple apices (Fig.2B-D). The case mimicked symptomatic apical periodontitis, but with just enough inconsistency to raise suspicion. For instance, the patient continued to experience cold sensitivity even after root canal treatments on teeth #26, #25, and #24. In hindsight, I believe his extremely low pain threshold may have caused any light contact, including the cotton pellet used in our cold test with Endo Ice\u2014to trigger pain.<\/p>\n

Moreover, complicating the diagnosis was the patient’s extensive trauma history: a former boxer, he had suffered repeated dental injuries and head trauma from a previous car accident, followed by Gamma Knife radiosurgery. These factors, combined with his current medication regimen for chronic pain, initially pointed dentists toward a diagnosis involving temporomandibular disorder and persistent odontogenic pain.<\/p>\n

I performed root-end surgery on the affected teeth and submitted the tissue for biopsy. The pathology report, which arrived a month later, was sobering: adenoid cystic carcinoma, a rare salivary gland malignancy known for its perineural invasion, slow progression, and late distant metastasis (1). The patient was promptly referred to oncology and underwent extensive surgical treatment. However, the adenoid cystic carcinoma had metastasized to the lungs, and he has since been enrolled in clinical trials.<\/p>\n

Shift in the Clinical Decision<\/strong><\/p>\n

What made this case so deceptive was its mimicry. The lesion looked endodontic. The symptoms resembled persistent apical periodontitis, albeit with some red flags, such as trismus, dysphagia, and pain radiating to the ears. These were possibly interpreted as signs of temporomandibular disorder, especially given the patient\u2019s complex medical and trauma history. But when the radiographic and clinical signs didn\u2019t match the expected healing trajectory, we chose to biopsy. This decision turned out to be lifesaving.<\/p>\n

Clinical and Teaching Lessons<\/strong><\/p>\n

This case reminds us of how we teach endodontic surgery, not just the technical aspects, but also the broader responsibility of differential diagnosis.<\/p>\n

In residency programs, we emphasize flap design, root-end resection, ultrasonic device, bioceramic materials and so on. But just as critical is pattern recognition\u2014the ability to identify when something doesn\u2019t fit. In academia, the educators should discuss with residents and dental students the importance of listening closely to the patient\u2019s description of pain, especially when it is constant, severe, and poorly localized. These are often red flags for something beyond the tooth.<\/p>\n

Identifying malignancies that imitate endodontic conditions early is key to avoiding treatment delays. Salivary gland cancers represent the second most frequent malignancy mimicking endodontic lesions, with metastatic tumors being the most common (2). More than 80% of malignancies mimicking endodontic pathology cause cortical bone destruction, and adenoid cystic carcinoma often exhibits perineural invasion that contributes to atypical pain patterns (2).<\/p>\n

In our case, the patient had no paresthesia or visible swelling, reminding us that the absence of classic signs doesn’t rule out serious disease.<\/p>\n

Practical Insights for Clinicians<\/strong><\/p>\n

From this experience, here are five practical clinical tips for clinicians:<\/p>\n