Differential Diagnosis
- Single most likely diagnosis:
- Hypochondriasis: This condition is characterized by a preoccupation with the fear of having, or the idea that one has, a serious disease, based on a person's interpretation of bodily symptoms, despite medical reassurance to the contrary. The scenario provided fits this description well, as the patient insists on having cancer despite investigations showing no abnormality.
- Other Likely diagnoses:
- Somatization: While somatization disorder involves multiple, recurring physical complaints without a clear medical cause, the patient's focus on a single condition (cancer) makes hypochondriasis more likely. However, somatization could be considered if the patient had a history of similar complaints about other diseases.
- Anxiety Disorder: The patient's persistent fear of having cancer could also be a manifestation of a broader anxiety disorder, where the fear of illness is one aspect of generalized anxiety.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Actual Malignancy with False Negative Tests: Although investigations revealed no abnormality, it's crucial to ensure that the diagnostic workup was comprehensive and that the possibility of a false negative result is considered, especially if the patient's symptoms or concerns persist.
- Psychotic Disorder: In rare cases, a fixed delusion about having a disease could be a symptom of a psychotic disorder. This would be more likely if the patient's belief is fixed and not amenable to change with reasoning or evidence to the contrary.
- Rare diagnoses:
- Factitious Disorder (Munchausen Syndrome): This involves the deliberate production or feigning of physical or psychological symptoms, primarily driven by a desire to assume the sick role. While possible, this diagnosis would require evidence that the patient is fabricating or inducing symptoms for attention.
- Delusional Disorder: Similar to psychotic disorder, but with a focus on a single delusion (in this case, having cancer), without the full symptom complex of schizophrenia. This would be considered if the patient's belief in having cancer is fixed and unshakable, despite clear evidence to the contrary.