Mycobacterium marinum Co-infection Masquerading as Treatment-Resistant Chromoblastomycosis: A Diagnostic and Therapeutic Challenge in Cutaneous Co-infection

Authors

  • Stefanus Soewito Sutanto Dermatology and Venereology, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia
  • Ni Luh Putu Ratih Vibriyanti Karna Dermatology and Venereology, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia/Department of Dermatology and Venereology, Faculty of Medicine, Universitas Udayana, Denpasar, Indonesia
  • Herman Saputra Pathology Anatomy, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia
  • Robert Thiodorus Dermatology and Venereology, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia

DOI:

https://doi.org/10.37275/bsm.v10i7.1624

Keywords:

Chromoblastomycosis, Co-infection, Fish tank granuloma, Mycobacterium marinum, Nontuberculous mycobacteria

Abstract

Background: Co-infection of chromoblastomycosis and Mycobacterium marinum (fish tank granuloma) within a single cutaneous lesion is exceptionally rare and presents a formidable diagnostic challenge owing to overlapping clinical and histopathologic features. The chronic verrucous or nodular morphology, predilection for distal extremities, and aquatic exposure history common to both conditions can lead to misdiagnosis, prolonged ineffective therapy, and patient morbidity.

Case presentation: A 31-year-old Indonesian male with a fishkeeping hobby presented with a persistent erythematous plaque on the right middle finger, present since 2022, following a puncture injury sustained while collecting mosquito larvae and water fleas as fish food. He was initially diagnosed with chromoblastomycosis (Phialophora spp. on culture) in September 2023 and treated with itraconazole 200 mg daily and topical miconazole 2% for 48 weeks without resolution. Repeat biopsy in 2024 demonstrated negative periodic acid-Schiff and Ziehl-Neelsen stains but revealed non-caseating tuberculoid granulomas. Considering the patient's aquatic exposure, antifungal failure, and granulomatous histopathology, a diagnosis of fish tank granuloma due to M. marinum co-infection was established. Combination antimycobacterial therapy with rifampicin 600 mg and ethambutol 1500 mg daily produced clinical resolution at six-month follow-up.

Conclusion: This case underscores the necessity of considering M. marinum in patients with antifungal-refractory chronic skin lesions and aquatic exposure, and highlights the diagnostic value of repeat histopathology with directed staining when initial therapy fails.

Authors

  • Stefanus Soewito Sutanto1
  • Ni Luh Putu Ratih Vibriyanti Karna2*
  • Herman Saputra3
  • Robert Thiodorus1
  1. 1Dermatology and Venereology, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia
  2. 2Dermatology and Venereology, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia/Department of Dermatology and Venereology, Faculty of Medicine, Universitas Udayana, Denpasar, Indonesia
  3. 3Pathology Anatomy, Prof. Dr. I.G.N.G Ngoerah General Hospital, Denpasar, Indonesia

Corresponding author Ni Luh Putu Ratih Vibriyanti Karna — ratihvibriyantikarna@gmail.com

Article history

  1. Submitted
  2. Accepted
  3. Published

Downloads

Published

2026-05-13

Article metrics

126Abstract views
80PDF downloads

How to Cite

1.
Stefanus Soewito Sutanto, Ni Luh Putu Ratih Vibriyanti Karna, Herman Saputra, Robert Thiodorus. Mycobacterium marinum Co-infection Masquerading as Treatment-Resistant Chromoblastomycosis: A Diagnostic and Therapeutic Challenge in Cutaneous Co-infection. Bioscmed [Internet]. 2026 May 13 [cited 2026 Aug. 6];10(7):2422-35. Available from: https://bioscmed.com/index.php/bsm/article/view/1624

Most read articles by the same author(s)