This case was reported in a literature article and described the occurrence of mucormycosis in a 4-year-old female patient who received DTaP vaccine. Co-suspect products included Polio Vaccine. Concurrent medical conditions included acute lymphocytic leukemia and immunocompromised. Concomitant products included methotrexate, vincristine and daunorubicin. On an unknown date, the patient received DTaP vaccine at an unknown dose and Polio Vaccine at an unknown dose and frequency. On an unknown date, 21 days after receiving DTaP vaccine, the patient experienced mucormycosis (serious criteria GSK medically significant), skin lesion, tenderness, skin plaque, pain and induration. The patient was treated with Liposomal Amphotericin B. On an unknown date, the outcome of the mucormycosis, skin lesion, tenderness, skin plaque, pain and induration were recovered/resolved. The reporter considered the mucormycosis, skin lesion, tenderness, skin plaque, pain and induration to be related to DTaP vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of mucormycosis in a 4-year-old female patient who was vaccinated with unspecified DTaP vaccine and unspecified polio vaccine (manufacturer unknown for both). The patient was an immunocompromised girl. The patient had newly diagnosed acute lymphocytic leukaemia, receiving her initial course of chemotherapy with vincristine, daunorubicin and methotrexate. No information on patient's family history was provided. On an unspecified date, the patient received unspecified DTaP and unspecified polio vaccine (administration route unspecified; dosages unknown; batch number not provided for both). Age of vaccination not provided. On an unspecified date, 3 weeks after vaccinations, the patient developed a painful lesion on her left triceps. The tender area was beneath an adhesive bandage placed where she had received the vaccines. The patient was otherwise, appeared remarkably well, and her vital signs were normal. Bandage removal revealed a tender indurated gray-violet plaque. White blood cell and neutrophil counts were low at 0.4 K/uL and 0.18 K/uL, respectively. Blood culture findings were negative. Punch biopsy specimens were obtained for histopathologic analysis and fungal culture. Histopathologic examination showed prominent broad non septated hyphae in the superficial and deep dermis surrounding and infiltrating several blood vessels, along with overlying areas of focal vacuolar interface changes at the dermal-epidermal junction. Microscopic examination of organisms grown from tissue culture revealed wide non septate hyphae with irregular branching, round terminal sporangia, and free spores. The histopathologic and tissue culture findings were consistent with a diagnosis of mucormycosis. The cutaneous lesion was completely excised. Treatment with intravenous liposomal amphotericin B was initiated. Her skin findings did not recur. The author did not comment on the relationship between mucormycosis and unspecified DTaP vaccine. The author stated, "A high index of suspicion is necessary for rapid diagnosis and intervention in fungal infections in immunocompromised patients. Suspicious skin lesions should be biopsied immediately for histopathological examination and tissue culture. A fungal wet-prep or prompt frozen processing of the biopsy specimen may expedite diagnosis. Proper antimicrobial therapy and debridement or excisional surgery should be initiated as soon as possible to increase the chances of survival."