Working Diagnosis:
Right knee ruptured epidermal inclusion cyst with brisk foreign body giant cell reaction
Treatment:
The patient underwent a right knee mass excision performed by an orthopedic surgeon.
Outcome:
At the two week postoperative mark, the patient reported right knee tightness, incision hypersensitivity, and postoperative vertigo.
At three months, the patient reported that the vertigo had resolved independently and returned to a healthy state. The patient did not experience any complications and has since happily returned to the pickleball courts.
Author's Comments:
Epidermal inclusion cysts are the most common benign cutaneous cysts that normally manifest in the upper extremity. Manifestation in the lower extremity is considered a rare pathology, with only four cases investigated since 2004. The current study provides another perspective to elucidate this rare pathology.
Editor's Comments:
When evaluating knee complaints, remember that just because a concern is next to a joint, that it doesn't necessary mean it's actually related to the joint. This case reminds us that sometimes, a mass near a joint is only skin deep.
References:
1. Bashaireh KM, Audat ZA, Jahmani RA, Aleshawi AJ, Al Sbihi AF. Epidermal inclusion cyst of the knee. Eur J Orthop Surg Traumatol. 2019 Aug;29(6):1355-1358. doi: 10.1007/s00590-019-02432-4. Epub 2019 Apr 9. PMID: 30968204.
2. Mayo M, Werner J, Joshi B, Abramovici L, Strauss EJ. An epidermal inclusion cyst mimicking chronic prepatellar bursitis: a case report. J Knee Surg. 2013 Dec;26 Suppl 1:S103-6. doi: 10.1055/s-0032-1324806. Epub 2012 Sep 21. PMID: 23288748.
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