September 2014

Misdiagnosis of Amalgam Tattoo Results in Failure to Diagnose Melanoma and Death of Patient

Mario Catalano, DDS, MAGD

Background: This edition of Malpractice Minute discusses a case involving a dental hygienist’s identification of what was believed to be an amalgam tattoo. Her reliance on the patient’s explanation for it, and her failure to consult with the dentist, led to a long delay in diagnosing what ultimately turned out to be a lesion indicating malignant melanoma.

Case discussion: The patient was a 26-year-old male who had no remarkable medical history. He had a dental history of palatal discoloration. The patient began treatment at the office of Dr. J a few months after his discharge from the military.

The patient was seen for an initial exam, prophylaxis, and radiographs; he required no additional treatment at that time. In the patient’s record, the hygienist noted that she observed a small discolored lesion on the palate, proximal to tooth 10. She recalls the patient telling her that he had the lesion biopsied while in the military and the diagnosis was an amalgam tattoo. However, she did not document that conversation. The patient continued with regular care, seeing the same hygienist for his cleaning and exams. During the course of his care, he had two restorations and biannual routine care.

About 6 years after the patient’s initial visit, the hygienist made a note in his record that the lesion on his palate was now about 5mm x 3 mm. She also noted a similar palatal lesion adjacent to teeth 12 and 13. The dentist made no entries regarding these lesions or any action taken in response to them.

Approximately 10 years into treatment, the patient saw a new hygienist, as the previous hygienist had left the doctor’s employment. This hygienist also expressed concern to the patient about the lesions, but did not document that conversation in the patient’s record. There continued to be no entries by the doctor relating to the lesions. The patient’s final appointment at this practice was shortly thereafter.

About 6 weeks later, the patient presented to an ENT surgeon with significant swelling and discomfort of the lymph nodes in his neck. He reported that his symptoms had been present for a few months. The physician ordered a biopsy, which indicated malignant melanoma. CT and MRI scans also were ordered, and they indicated numerous lesions on his liver and spine. Because of the grim prognosis, palliative treatment was ordered, and the patient died 10 weeks later at age 36.

A lawsuit was filed against the dentist (both individually and as the employer of the hygienists) alleging negligent failure to diagnose the malignant melanoma at a time when it could have been treated. With the doctor’s consent, the case was settled in the high range, with expenses in the midrange.



Risk Management Considerations

Theodore Passineau, JD, HRM, RPLU, CPHRM, FASHRM

Patients are injured in the process of receiving dental care for many reasons. Sometimes, a single person makes a single mistake, such as treating the wrong tooth, using the wrong medication, forgetting a step in the treatment process, etc. Although dental providers are as careful as possible, these types of errors cannot completely be prevented because of the human propensity to make mistakes. Instead, providers use techniques such as double checking, redundant systems, and checklists to minimize the potential for error.

Other errors are the result of systemic failure. Factors such as miscommunication, failure to communicate, differing assumptions, and other process failures can result in improper care, leading to patient injuries.

This case contains elements of both types of errors. The first error occurred during the intake process for this new patient. New patient intake should include a complete medical and dental history, followed by a thorough oral exam. This establishes the treatment starting point, which is essential to a retrospective understanding of the case, and identifies:

  • The patient’s present dental needs;
  • Any circumstances that will complicate treatment, such as allergies, current use of bisphosphonates, etc.; and
  • Any abnormal conditions (medical or dental) that require immediate investigation.

Although a patient’s medical and dental history form will not reveal a suspicious lesion, a thorough oral examination will. At that point, certain steps should be taken, starting with the measurement and (if possible) photographing of the lesion. The patient should be questioned specifically about the lesion (which was done in this case); however, the dentist should not rely on the patient’s explanation of the condition as authoritative. Over many years, patients have demonstrated their tendency to be poor historians.

It is always very helpful to review the patient’s previous dental records; however, in certain circumstances, they may not be available or may be very difficult to acquire. In such a case, any abnormalities should be treated as a newly arising condition, which must be investigated to a final diagnosis. In this case, the patient’s previous dental records might have been difficult to acquire from the military. Thus, the lesion should have been biopsied if the dentist was not absolutely positive regarding the diagnosis from visual examination.

Another issue in this particular case was the failure of both hygienists to document their conversations with the patient regarding the lesion. Whenever the patient provides clinically significant information, the information should be documented. Directly quoting the patient is an effective way to accomplish this.

The complete lack of documentation by the dentist in this case calls into question what he actually knew during this roughly 10-year period of treatment. It also calls into question whether the dentist was doing oral exams at the conclusion of the cleanings or at any other time.

The lack of documentation, combined with apparently inadequate evaluation of the lesions, led to a malpractice suit in which the care provided by Dr. J could not be successfully defended.

Conclusion: Many dental malpractice claims involve allegations of failure or delay in diagnosing diseases or conditions. Careful attention to changes in the patient’s oral health, accompanied by appropriate documentation of those changes, can help ensure patients receive optimal care and help minimize exposure to professional liability.

Question: When a new patient presents with an abnormal condition, what steps should the dental care team take to ensure appropriate provision of care?