10.5826/dpc.1302a102
text/xml
2160-9381
2731
en
Piergiacomo Calzavara-Pinton
https://creativecommons.org/licenses/by-nc/4.0
Dermatology Practical & Conceptual
“Dot in a Circle”: an Useful Ultrasound Finding for a Rapid Diagnosis of Mycetoma
Text.Serial.Journal
https://dpcj.org/index.php/dpc
Image Letter
2023-04-29
2022-07-29
2023-04-29
2023-06-05
e2023102
Dermatol Pract Concept
Piergiacomo Calzavara-Pinton
2023/04/29
10.5826/dpc.1302a102
e2023102
Department of Dermatology, Spedali Civili, University of Brescia, Brescia, Italy 
2160-9381
en
e2023102
Petscavage JM, Richardson ML. Madura foot masquerading as a hemangioma. Radiol Case Rep. 2015 Nov 6;5(1):355.
“Dot in a Circle”: an Useful Ultrasound Finding for a Rapid Diagnosis of Mycetoma
https://dpcj.org/index.php/dpc/article/download/2731/2099
        “Dot in a Circle”: a Useful Ultrasound Finding
             for a Rapid Diagnosis of Mycetoma
              Vincenzo Maione1, Chiara Cozzi1, Marina Venturini1, Angela Napolitano2,
                                 Piergiacomo Calzavara-Pinton1


1 Department of Dermatology, Spedali Civili, University of Brescia, Brescia, Italy
2 Department of Neuroradiology, ASST Papa Giovanni XXIII, Bergamo, Italy



Citation: Maione V, Cozzi C, Venturini M, Napolitano A, Calzavara-Pinton P. “Dot in a Circle”: an Useful Ultrasound Finding for a Rapid
Diagnosis of Mycetoma. Dermatol Pract Concept. 2023;13(2):e2023102. DOI: https://doi.org/10.5826/dpc.1302a102
Accepted: September 25, 2022; Published: April 2023
Copyright: ©2023 Maione et al. This is an open-access article distributed under the terms of the Creative Commons
Attribution-NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted
noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited.
Funding: None.
Competing Interests: None.
Authorship: All authors have contributed significantly to this publication.
Corresponding Author: Vincenzo Maione, Department of Dermatology, Spedali Civili, University of Brescia, Brescia, Italy.
Tel +39 030 3995301 Fax +39 0303995015 E-mail: maionevincenzo@gmail.com




Case Presentation                                                         our hypothesis of mycetoma. In addition an underlying
                                                                          osteomyelitis was diagnosed (Figure 1C). After a first nega-
A 65-year-old man from Senegal presented to our Clinic                    tive culture, we collected new skin samples under ultrasound
with a 15-year history of a nodular enlarging mass on his                 guidance which resulted positive for Staphylococcus caprae
left foot. Clinical examination revealed a large painless                 and Bacillus pumilus. The patient was treated with ampicillin,
lesion with crusting and purulent discharge (Figure 1A).
­                                                                         after a surgical debulking.
The lesion gradually enlarged, leading to deformity and
walking impairment. Before biopsy, we performed an ul-
                                                                          Teaching Point
trasonography which showed hypoechoic areas containing
hyperechoic foci, a typical “Dot in a circle” sign (Figure 1B).           Madura foot or mycetoma is endemic disease in tropical
A ­subsequent MRI of the foot confirmed ultrasound find-                  ­regions and takes its name from the Indian city of ­Madurai,
ings, revealing well-defined hyperintense lesions with periph-            where it was described for the first time. Its clinical pre-
eral hypointense rim and central hypointensities, confirming              sentation, typified by sinuses, subcutaneous nodules and




Image Letter | Dermatol Pract Concept. 2023;13(2):e2023102                                                                            1
Figure 1. (A) Painless mass of the plantar surface of the left foot with a purulent discharge. (B) Ultrasound (14-20 MHz Us Transducer –­
MylabTMOne, Esaote) evidenced a hypoechoic area containing hyperechoic foci, due to granulomatous reaction to bacteria grains.
(C) Sagittal T2 weighted STIR MRI confirms the presence of “dots in a circle sign” associated to osteomyelitis.



purulent discharge, is due to a granulomatous reaction to             helps appropriate specimen ­collection for culture, ­avoiding
fungal ­hyphae (Eumycetoma) or bacteria (Actinomycetoma)              multiple surgical interventions.
­aggregates - the “grains” [1]. These pathological findings can
be assessed with different diagnostic tools. For instance, Der-
moscopy displays multiple papules, disappearance of skin              References
furrows and fistulous tracts extruding grains. In additional           1. Verma P, Jha A. Mycetoma: reviewing a neglected disease. Clin
other dermoscopic features include blood spots, erosions,                 Exp Dermatol. 2019;44(2):123-129. DOI: 10.1111/ced.13642.
orange-yellowish structureless areas [2]. Ultrasonography                 PMID: 29808607.
seem to be more specific showing a peculiar aspect called “dot         2. Errichetti E, Ankad B, Chatterjee M, Calzavara-Pinton P, M
                                                                                                                                   ­ aione V,
                                                                          Chauhan P. Mycosis. In: Dermoscopy in General Dermatology for
in a circle” [3], which correlates directly with the presence of
                                                                          skin of Color. Errichetti E, Lallas A (Eds) 1th ed. 2022:132-133.
grains. ­Microbiological culture from skin biopsy is necessary
                                                                          DOI: 10.1201/9780367816483.
to confirm diagnosis but often results difficult, delaying treat-      3. Petscavage JM, Richardson ML. Madura foot masquerading as
ment. Ultrasound is rapid and low-cost technique – available              a hemangioma. Radiol Case Rep. 2015;5(1):355. DOI: 10.2484
also in Dermatology Clinics- which assists early ­diagnosis and           /rcr.v5i1.355. PMID: 27307847. PMCID: PMC4898212.




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