Case of the Month: November 2024
Clinical history
A 6-year-old girl is brought to the emergency room by her parents. She has developed a painless swelling on her left thigh that has gradually increased in size over the past two months. Initially, her parents thought it was a bruise or injury from playing, but the swelling became progressively larger and more firm. Recently, she has experienced some difficulty walking and now has a noticeable limp.
On examination, her temperature is 37.5°C, blood pressure 105/70 mmHg, heart rate 105 beats per minute, and respiratory rate 20 per minute. There is a firm, non-tender mass in her left lateral thigh, measuring approximately 6 cm in diameter. The overlying skin is mildly erythematous, but there is no evidence of warmth. On neurological examination, there are no signs of weakness, but she has a reduced range of motion in her left hip due to the mass.
A CT scan confirms the presence of a large heterogenous mass in the left thigh, without evidence of lymph node involvement or distant metastasis. A biopsy is taken and sent to pathology.
Questions:
- What are three (3) differential diagnoses for a small round blue cell tumour involving the bone or soft tissue in the pediatric population?
- What are four (4) immunohistochemical stains you could use to assess this lesion?
- Why are molecular studies (e.g. looking for specific gene fusions or mutations) often important in pediatric malignancies?
How to participate
Take a look at the images.
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If you are a medical student at the University of Toronto, you can also:
If you do, you are in for a chance to win a $100 gift card! (UofT Med students only).
If you are a current medical student at U of T, you can register to join the November case of the month lecture online or in person and have a chance to win a $100 gift card!
You can also join the Special Interest Group in Laboratory Medicine to learn more about Laboratory Medicine.
Laboratory Medicine and the study of disease for medical students
