From Clinical Reasoning to a Differential Diagnosis
The navel is, for obvious reason, an important area in the immediate postpartum. Later on in life is only a place prone to infection and the presence of an intestinal hernia, but, on some occasions it is also a place where we can find a surprise.
In this clinical case we want to enhance the importance of a Differential diagnosis, even when we see almost crystal clear that we have the answer to the problem.
A 72-year-old woman had a previous diagnosis of endometrial carcinoma limited to the uterus. Two years after she finished Radiotherapy and Chemotherapy, she developed abdominal metastases and she received a second line of treatment. In the last three months she went to the Emergency Department (ED) referring abdominal pain and nausea, and in two occasions she was discharged home with a diagnosis of an umbilical hernia.
One week before the hospital admission, she went again to the ED with almost the same symptoms than before, abdominal pain, nausea and vomiting. We show here a second picture of the lump inside the navel.
Clinical Reasoning Exercise
When you see a patient like her, your brain recovers a pattern of an umbilical hernia. This is correct because is clear that there is intestinal material protruding the umbilical region. But, then you start with the physical examination and you feel that the lump is hard, and then you think, recovering the previous information about endometrial cancer, that your patient can have a Sister Mary Joseph´s nodule. But then you recover again the few experiences that you have with this type of nodule, no more than two or three in the whole of your career, and you remember that usually the size is not so big. The, after all this pattern recognition exercise you set your differential:
- Umbilical hernia
- The Sister Mary Joseph nodule
Finally, you get the information from the CT scan: a structure composed of an intestinal loop with metastases around the intestinal fat.
In this case probably the mechanism involved in this lesion is multiple, but we really don´t know how the cancer cells reached the navel. We know that the mechanism involved in the Sister Mary Joseph´s nodule is the retrograde dissemination of cancer cells via the residual round ligament.
The final clinical judgment requires an integration of the anamnesis, physical examination and the specific diagnostic tests. Only after this information is integrated into the brain the emission of a clinical judgment is safe for everyone. In this case the first impression changed after the physical examination showed a “hard” lump.
You can see some pictures of a nodule of the Sister Mary Joseph here.
Author: Dr. Lorenzo Alonso