A 1-year-old female presented with a few-week history of an anterior upper chest lesion. The lesion was associated with redness and tenderness. Her past medical and surgical histories were unremarkable, with no significant family history. She was not taking any regular medications. Physical examination showed on inspection a solitary, approximately 3–4 cm, well-demarcated, hemispherical cutaneous swelling with a smooth, tense, shiny surface and overlying erythema. The lesion is predominantly erythematous with a mildly crusted/scaly apex. No obvious ulceration, bleeding, or active discharge is evident. The surrounding skin shows no marked extension of erythema or visible lymphangitic spread. On Palpation the lesion was tender, warm, and firm in consistency, with a well-defined margin and relative mobility over the underlying tissues.

Complete blood count showed a WBC count of 11.0 × 10⁹/L, within the age-specific reference range, with a normal differential count. Hemoglobin was 11.8 g/dL, hematocrit 34.4%, and platelet count 439 × 10⁹/L, all within the provided reference ranges. Red blood cell indices were also within the expected range for age. Thyroid function tests were within normal limits, with TSH 1.03 µIU/mL and FT4 19.38 pmol/L.The CRP was 2.79 mg/L, which is within the normal range (<5 mg/L), with no significant elevation of this inflammatory marker. Overall, the laboratory investigations showed no significant leukocytosis, anemia, thrombocytopenia, or biochemical evidence of significant systemic inflammation.

In the left upper chest skin and subcutaneous tissues, there was a 21 × 18 × 14 mm complex cystic nodule with mild peripheral vascularity and marked surrounding inflammatory changes. An approximately 11-mm tract-like extension was seen extending from the lesion and nearly connecting to the skin surface. The findings were most suggestive of a complicated epidermoid cyst, although other etiologies could not be completely excluded.

Both lobes of the thyroid gland were normal in size and echotexture, with no focal lesions identified. The bilateral submandibular and parotid glands were also normal, with no focal lesions.

Under general anesthesia, the patient was positioned supine. An elliptical incision was made over the lesion, and the mass was carefully excised from the upper chest. Hemostasis was secured, and the wound was closed in layers. No drain was inserted. The excised tissue was sent for histopathological examination (HPE).

Histopathology of the upper chest wide local excision revealed a ruptured and inflamed epidermal inclusion cyst. The lesion was characterized by a cystic cavity within the dermis surrounded by a dense mixed inflammatory infiltrate, multinucleated giant cells, capillary proliferation, and fibrosis, with only a small remnant of the keratinizing stratified squamous epithelial lining identified. The overlying epidermis showed acanthosis, neutrophilic exocytosis, and reactive atypia. A possible tract-like extension to the skin was identified grossly. There was no evidence of dysplasia or invasive carcinoma, confirming a benign ruptured and inflamed epidermal inclusion cyst with no malignancy.

The patient had an uncomplicated postoperative course following wide local excision of the upper chest lesion under general anesthesia. The patient was discharged in stable condition with routine wound care advice and scheduled for postoperative follow-up to assess wound healing.