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Case Reports
. 2012:2:66.
doi: 10.4103/2156-7514.103056. Epub 2012 Oct 31.

The "dot in circle" sign on MRI in maduramycosis: a characteristic finding

Vikash Jain  1 , Gopee E Makwana, Nandini Bahri, Manish K Mathur
Affiliations
Case Reports

The "dot in circle" sign on MRI in maduramycosis: a characteristic finding

Vikash Jain et al. J Clin Imaging Sci. 2012.

Abstract

Mycetoma or Maduramycosis is a localized chronic suppurative infection characterized by exuberant granulation tissue, discharging sinuses, and bone involvement later in the course of the disease. Early clinical diagnosis before the appearance of sinuses and grains (aggregates of organism surrounded by granulation tissue, which are discharged from the draining sinuses) is difficult. Delay in diagnosis may lead to amputation of the affected part. Definitive diagnosis is through biopsy and microbiological examination. However, at times diagnosis may still be difficult. The recently described "dot in circle" sign on magnetic resonance imaging (MRI) is easy to recognize and highly specific. We present a case of mycetoma foot with characteristic MRI features.

Keywords: Dot in circle sign; MRI; maduramycosis; mycetoma.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Chronic osteomyelitis. A 48-year-old man with painless swelling of left foot. Frontal radiograph shows moth eaten area of destruction involving tarsal (white arrow) and metatarsals (black arrow) with patchy erosions and mild soft tissue swelling (yellow arrow).
Figure 2
Figure 2
MRI T2 weighted coronal images show inflammatory changes with multiple soft tissue and osseus small hyperintense lesions with peripheral hypointense rim corresponding to mycetoma grains (yellow arrows). Few of them showing “dot in circle” sign (thicker white arrow).
Figure 3
Figure 3
(a) T2 weighted fat suppressed sagittal and (b) T1W fat suppressed postcontrast sagittal images show extension of inflammation proximally up to distal leg with ankle joint effusion (yellow arrow) and synovial thickening. “Dot in circle” sign (white arrow) is seen in postcontrast image.
Figure 4
Figure 4
Histopathology slide prepared using lactophenol cotton blue shows septated conidia which is curved at 3rd cell from the base (yellow arrow) confirming the diagnosis of curvularia lunata (eumycetoma sp.) ×1500.
See this image and copyright information in PMC

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