A Rare Case of Osteomyelitis Caused by Scedosporium Apiospermum in the Right Foot of an Immunocompetent Patient

Abstract

Background: Fungal osteomyelitis is rare in clinical practice, and osteomyelitis caused by Scedosporium apiospermum is even rarer, which is easy to misdiagnose, and it is resistant to many antifungal drugs, which makes it tricky to treat. Early diagnosis and accurate treatment are essential.

Case presentation: A 38-year-old healthy male has been experiencing recurrent pain in his right foot, accompanied by skin ulcers and exudate, for the past five years. He has been diagnosed with bacterial osteomyelitis at other hospitals as well as at our hospital. In the first stage, osteomyelitis lesion removal + vancomycin bone cement tamponade was used, and the infected bone tissue was taken for microbial culture and morphological observation, and identified as Scedosporium apiospermum. The patient was cured after postoperative treatment with voriconazole. No further signs of infection or Scedosporium apiospermum were detected during the second stage of bone reconstruction surgery, and the incision healed with grade A healing and no further signs of osteomyelitis, such as bone destruction, were detected after bone reconstruction surgery.

Conclusion : This is a rare case of Scedosporium apiospermum osteomyelitis of the right foot, which was successively misdiagnosed and finally cured by surgery and antifungal treatment with voriconazole. Given that Scedosporium apiospermum is extremely rare and resistant to antifungal drugs, this case highlights the importance of microbiologic culture and pathologic examination, surgical debridement, and precise antifungal treatment.

Keywords: antifungal treatment; foot; osteomyelitis; scedosporium apiospermum; surgical debridement.

Figure 1

Pre-operative DR. (A) anteroposterior projection, (B) lateral projection, and (C) oblique projection.

Figure 2

Pre-operative CT. (A) Coronal view, (B) sagittal view, and (C) axial view.

Figure 3

Postoperative DR for one-stage surgery. (A) anteroposterior projection, (B) oblique projection.

Figure 4

(A) Intraoperative findings during the first-stage surgery: Bone destruction and complete necrosis of the lateral cuneiform bone of the right foot, with partial sclerosis and destruction of the dice bone, navicular bone, third and fourth metatarsals, and middle cuneiform bone. A small amount of yellow pus and granular, crab roe-like material (indicated by the arrow) were observed. (B) Intraoperative findings during the second-stage surgery: The wound healed well with no redness or swelling. Upon cutting through the skin, no exudate was observed around the bone cement, and the induced membrane was clean without secretions. There was no significant bone destruction or sclerotic bone.

Figure 5

(A–B) October 18, 2023 The microbial culture and identification showed that after 3 days of culture, no bacterial growth was observed in the routine culture. Upon extending the culture period, a small amount of Scedosporium growth was observed, morphologically considered Scedosporium apiospermum.

Figure 6

October 19, 2023 The pathological diagnosis report indicates: “The submitted tissue from the right foot shows acute suppurative inflammation with abscess formation, necrosis, and granuloma formation. Fungal spores and hyphal-like structures are visible within. Please correlate with laboratory tests. Fluorescent immunohistochemical staining: positive (+)”.

Figure 7

Postoperative DR for second-stage surgery. (A) anteroposterior projection, (B) lateral projection, and (C) oblique projection.

Figure 8

5-month postoperative review of DR after second-stage surgery. (A) anteroposterior projection, (B) lateral projection, and (C) oblique projection.