Postvaccination Abscess Caused by Mycobacterium tuberculosis in a 2-year-old Boy

Dear Sir, We read with great interest the recent article by Shah et al. in JIAPS, describing 13 cases of postvaccination abscesses caused by nontuberculous mycobacteria (NTM).[1] We commend the authors for highlighting this rare but significant complication. We encountered a similar case in a 2-year-old boy with a postvaccination abscess due to Mycobacterium tuberculosis. The boy presented with a persistent swelling on his left thigh following an intramuscular influenza vaccination at 6 months of age [Figure 1a]. Ultrasonography of the lesion revealed a well-defined cystic mass measuring approximately 2.6 cm × 1.7 cm × 5 cm, with internal echoes and some calcification foci, located in the subcutaneous plane [Figure 1b]. Complete surgical excision of the swelling was done [Figure 1c]. On opening the specimen, 10–20 mL white, nonfoul smelling, thick pus was seen which was positive for acid-fast bacilli on Ziehl–Neelsen staining and GeneXpert confirmed M. tuberculosis [Figure 1d and e]. The child was treated successfully with anti-tubercular therapy and remains symptom-free after 1 year.Figure 1: (a) Swelling of size 5 cm × 3 cm on the antero-lateral aspect of left thigh (arrow) (b) Ultrasonography of the lesion showing a well-defined cystic mass located in the subcutaneous plane with internal echoes and few calcific foci (c) Intra-operative image showing excision of abscess cavity with thick, irregular, poorly defined wall densely adherent to the surrounding structures (d) Thick, white, nonfoul smelling pus present inside abscess cavity (e). Microscopy image of Ziehl-Neelsen staining of smears from the pus showing acid-fast bacilli (arrows)This case and the series by Shah et al.[1] stress the importance of considering M. tuberculosis and NTM as differential diagnoses for chronic postvaccination abscesses. Prompt diagnosis and appropriate management are crucial for favorable outcomes. Further research into the etiology of these infections is warranted.[2] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.