CASE 12928 Published on 02.10.2015

Distal femoral cortical irregularity with diaphysis fracture

Section

Paediatric radiology

Case Type

Clinical Cases

Authors

Saliha Çıracı¹, Selim Doganay¹, İbrahim Halil Kafadar², Burcu Süreyya Görkem¹, Alper Özcan³, Gonca Koç¹, Abdulhakim Coşkun¹

(1) Department of Radiology
(2) Department of Orthopedy
(3) Department of Pediatric Hematology
Erciyes University, School of Medicine

Patient

6 years, female

Categories

Area of Interest Musculoskeletal bone ; Imaging Technique Digital radiography, CT, MR

Procedure Imaging sequences ; Special Focus Trauma ;

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Clinical History

A 6-year-old girl presented with pain in her left leg. The patient had a history of trauma to the left lower extremity a month before.

Imaging Findings

Anteroposterior radiography of the leg showed a solid periosteal reaction on the proximal femoral diaphysis (Fig. 1). Radiography had not involved the knee.
Computed tomography (CT) showed a solid periosteal reaction and fracture on the medial aspect of the proximal femoral diaphysis (Fig. 2).
On CT, an irregular cortical defect was seen on the distal medial femoral metaphysis at the attachment of the medial head of the gastrocnemius muscle (Fig. 3).
On MR, the proximal diaphysis of the femur was hyperintense on T2W images, hypointense on T1W images due to oedema (Fig. 4).
MR imaging showed an oval-shaped, 11x9x6 mm sized lesion on the posteromedial distal femoral metaphysis. The lesion was iso-hypointense to muscle on T1W images and hyperintense on T2W image. On postcontrast T1W series the lesion enhanced (Fig. 5).

Discussion

Distal femoral cortical irregularity (DFCI) is a benign entity presenting as an irregular, destructive cortical lesion on the posteromedial aspect of the distal femoral metaphysis. DFCI on radiographs of distal femur has been reported in 11.5% of male and 3.6% of female children [1]. DFCI shows a definite predilection for children and adolescents, and certainly a relation to stress [2]. The lesions are bilateral in approximately 35% of cases [3].
Distal femoral cortical irregularity has also been referred to as “cortical desmoid”, “cortical irregularity syndrome” and “distal femoral defect” [4].
The typical radiological appearance is a radiolucent cortical defect with adjacent sclerosis. It is often asymptomatic and is almost an incidental finding [3].
CT imaging shows cortical erosion at the origin of the medial head of the gastrocnemius or fibres of adductor magnus muscle. Small fragments of resorbing bone may be seen in the lesion [4].
On MRI, DFCI is hypointense on T1-weighted images and hyperintense on T2-weighted images. A dark rim may be seen on both sequences. The lesion is typically at or near the sites of the bony attachment of the medial head of the gastrocnemius muscle [5].
Bone scintigraphy with technetium typically shows no increased uptake in the area of DFCI [6].
Because of the immature reactive bone and fibrous tissue involvement, DFCI has been mistaken for osteosarcoma histologically. It is usually possible to identify these lesions radiologically and avoid biopsy [3]. DFCI is a 'do not touch' lesion which is not known by all radiologists and which can lead to unnecessary follow-up imaging.

Differential Diagnosis List

Distal femoral cortical irregularity

Osteosarcoma

Nonossifying fibroma

Final Diagnosis

Distal femoral cortical irregularity

References

[1] Craigen MA et al. (1994) Symptomatic cortical irregularities of the distal femur simulating malignancy. J Bone Joint Surg Br 76(5):814-7 (PMID: 8083276)

[2] Resnick D, Greenway G. (1982) Distal femoral cortical defects, irregularities, and excavations. Radiology 143(2):345-54 (PMID: 7041169)

[3] Dunham WK, Marcus NW, Enneking WF, Haun C. (1980) Developmental defects of the distal femoral metaphysis. J Bone Joint Surg Am 62(5):801-6. (PMID: 6930380)

[4] Pennes DR, Braunstein EM, Glazer GM. (1984) Computed tomography ofcortical desmoid. Skel Radiol 12(1):40-2 (PMID: 6474218)

[5] Yamazaki T, Maruoka S, Takahashi S, Saito H, Takase K, Nakamura M, Sakamoto K. (1995) MR findings of avulsive cortical irregularity of the distal femur. Skeletal Radiol 24(1):43-6. (PMID: 7709251)

[6] Burrows PE, Greenberg ID, Reed MH. (1982) The distal femoral defect: technetium-99 m pyrophosphate bone scan results. J Can Assoc Radiol 33:91–93

Case information

URL:	https://www.eurorad.org/case/12928
DOI:	10.1594/EURORAD/CASE.12928
ISSN:	1563-4086

License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Figure 1

AP X-ray

Anteroposterior radiography of the leg showed a solid periosteal reaction on the proximal femoral diaphysis.

Figure 2

Coronal CT of the leg demonstrated fracture and solid periosteal reaction on proximal femoral diaphysis.

Axial CT of the leg showed fracture on proximal femoral diaphysis.

Axial CT of the leg showed solid periosteal reaction on proximal femoral diaphysis.

Figure 3

Axial CT of the knee demonstrated cortical irregularity on posteromedial aspect of distal femoral metaphysis.

Coronal CT of the knee showed cortical irregularity on posteromedial aspect of distal femoral metaphysis.

Figure 4

MRI

The proximal diaphysis of the femur was hyperintense on T2W images due to oedema.

The proximal diaphysis of the femur was hypointense on T1W images due to oedema.

Figure 5

MRI

Coronal MR imaging showed an oval-shaped, 11x9x6 mm sized lesion on the posteromedial distal femoral metaphysis. The lesion was hyperintense to muscle on fat satured T2W image.