Brodie’s abscess, first described by Sir Benjamin Brodie in 1832 as a “chronic abscess of the tibia”, is a localised form of subacute or chronic osteomyelitis. It is characterised by a collection of pus surrounded by a sclerotic wall and most commonly affects the metaphysis of long bones, particularly the tibia (48.6%) and femur (31.3%). Clinical presentation typically includes localised pain and swelling with minimal or absent systemic features, often resulting in delayed diagnosis.

Although rare (4.6%), Brodie’s abscess has been reported in several tarsal bones, most notably the cuboid, ^,,,,, calcaneus, ^,,, and talus, ^,,, predominantly as isolated case reports in both adult and paediatric populations.

In a systematic review of 407 cases, diagnostic imaging included plain radiographs in nearly all cases, with MRI used in approximately 16% and CT in 8%. Radiographically, Brodie’s abscess typically appears as a well-defined lytic lesion with a surrounding sclerotic rim, although appearances may vary and mimic benign or malignant bone tumours. MRI is particularly useful in identifying marrow oedema and the characteristic penumbra sign, defined as a rim of relatively higher signal intensity surrounding the abscess cavity, while SPECT-CT may assist in diagnostically challenging cases.

Bacterial spread is most commonly haematogenous, with Staphylococcus aureus being the predominant organism, although culture-negative disease is frequently encountered, particularly following prior antibiotic exposure. ^,, Surgical debridement combined with culture-directed antibiotic therapy remains the mainstay of treatment. ^,,

To the authors’ knowledge, there are no previously reported cases of Brodie’s abscess involving the medial cuneiform. We therefore present this case.

A 30-year-old male presented with a long-standing history of a fluctuant cystic lesion over the dorsomedial aspect of his right midfoot. He was otherwise fit and well (ASA grade II) with a body mass index of 45 kg/m². He was a non-smoker, consumed minimal alcohol, and worked in steel fabrication, routinely wearing safety boots. His medical history was significant for congenital talipes equinovarus, surgically corrected in early childhood with bilateral Heyman–Herndon procedures.

The lesion had been present for 2–3 years, intermittently breaking down with a creamy discharge and associated moderate pain, occasionally disturbing sleep. Review of the primary care records identified four documented courses of oral antibiotics prior to definitive diagnosis, including three courses of flucloxacillin and one course of co-amoxiclav, all of which provided only temporary symptomatic relief.

Clinical examination revealed an intact cystic lesion adjacent to the naviculocuneiform joint, close to the extensor hallucis longus tendon, with localised erythema but no active discharge. There were no neurovascular abnormalities, and the remainder of the foot examination was unremarkable.

Ultrasound demonstrated a well-defined, non-specific mass on the dorsomedial aspect of the foot, with a sinus tract extending from the underlying bone to the skin surface. An excision biopsy of the lesion was performed on an expedited basis to facilitate histopathological and microbiological analysis. Histopathological examination demonstrated acute-on-chronic inflammatory changes without evidence of malignancy, while microbiological culture yielded no organisms of significance. Despite initial clinical improvement, the patient subsequently developed recurrent wound breakdown and a new adjacent subcutaneous lesion ( Fig. 1 ).

Photographs showing new lesion (orange) adjacent to the original wound (blue) which is between two bone biopsy sites (green).

Subsequent review by the local musculoskeletal radiologist identified a well-circumscribed lucency with a sclerotic rim within the medial cuneiform on plain radiographs ( Fig. 2 ), raising suspicion of a simple bone cyst or Brodie’s abscess.

Plain radiographs of the right foot demonstrating a well-defined lucency within the medial cuneiform with a surrounding sclerotic rim, consistent with a Brodie’s abscess.

Magnetic resonance imaging (MRI) ( Fig. 3 ) demonstrated an intraosseous cavity within the medial cuneiform with extensive marrow oedema, adjacent soft-tissue inflammation and a sinus tract extending dorsally to the skin surface. No discrete abscess collection was identified. The appearances were consistent with chronic osteomyelitis (Brodie’s abscess).

MRI of the right foot demonstrating an intraosseous cavity within the medial cuneiform with surrounding marrow oedema and a sinus tract extending dorsally towards the skin surface.

Bone biopsies of the medial cuneiform confirmed chronic osteomyelitis on histopathological examination; however, microbiological cultures remained negative following both 7 and 14 days of incubation. Following excision of the superficial lesion, the patient received a further two-week course of flucloxacillin. In accordance with local outpatient osteomyelitis treatment guidelines, treatment was subsequently changed to doxycycline 100 mg twice daily for six weeks and the patient was monitored with serial radiographs and inflammatory markers. Serial blood investigations remained largely unremarkable throughout treatment, with C-reactive protein remaining only mildly elevated, decreasing from 7.3 mg/L at presentation to 3.3 mg/L during follow-up, while renal and liver function remained within normal limits.

Owing to persistent radiological abnormality and delayed wound healing, definitive surgical management was undertaken. Debridement of the medial cuneiform was performed with copious saline lavage and the resulting defect packed with antibiotic-impregnated bone substitute (Cerament G®). During debridement, a retained FibreWire suture was identified within the medial cuneiform and removed. This material, presumed to have originated from the childhood talipes surgery, was considered the most likely nidus for chronic infection and may have contributed to the poor response to repeated systemic antibiotic therapy.

Histopathological examination confirmed acute-on-chronic osteomyelitis with no evidence of malignancy. Microbiological sampling from the curettage tract subsequently isolated Enterobacter cloacae together with scant growth of Staphylococcus epidermidis . Clinical resolution was achieved following definitive surgical debridement and implantation of gentamicin-loaded Cerament G®. No further systemic antibiotic therapy was prescribed following microbiological results.

Follow-up radiographs demonstrated no convincing radiological evidence of ongoing osteomyelitis, and at six-month review the patient remained asymptomatic with complete wound healing and no clinical or radiological evidence of recurrence.