PMC4296270_01
US, PET/CT, chest CT and pathologic findings of charcoal-induced granuloma.. Preoperative US (A) shows several hypoechoic nodules with well-defined margins (arrows) and one well-defined, isoechoic nodule (broken arrow) with internal high echoic dots in right level IV. These lymph nodes were localized using charcoal and revealed metastatic lymph nodes with perinodal infiltration. Follow-up US at 6 months (B) shows irregularly shaped, hyperechoic nodule measuring 9.8 mm with indistinct margin with adjacent sternocleidomastoid muscle and fat of posterior cervical space (arrows). On 2-year follow-up US for US-guided core biopsy (C), compared to previous US (B), echogenicity of nodule decreased, and posterior acoustic shadowing was prominent (arrows). Six-month, initial follow-up FDG-PET and PET/CT (D) shows hypermetabolic nodule (SUVmax = 4.0) at right level IV (arrow). FDG = fluorodeoxyglucose, PET = positron emission tomography, SUVmax = maximum standardized uptake value, US = ultrasonography. Lesion is still hypermetablic (SUVmax = 4.3) (arrow) on 18-month follow-up FDG-PET and PET/CT (E). Precontrast chest CT (F) acquired at same day shows slightly hyperdense, oval-shaped nodule at lateral aspect of right internal jugular vein (arrow). Postcontrast CT (G) shows no definite enhancement of nodule (arrow). Gross specimen (H) shows black-pigmented soft tissue fragment. Microscopic image (H&E staining, x 300) (I) shows black pigments suggesting charcoal particles (asterisks) surrounded by multinucleared giant cells (arrows) and fibrosis (broken arrow). FDG = fluorodeoxyglucose, PET = positron emission tomography, SUVmax = maximum standardized uptake value, US = ultrasonography
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F1
She had undergone breast-conserving surgery and excision of a metastatic lymph node (Fig. 1A) 3 years prior. On her first follow-up FDG-PET/CT (Fig. 1D), which was performed 6 months after completion of treatment, a focal hypermetabolic lesion (maximum standardized uptake value [SUVmax] = 4.0) was noted at the lateral aspect of the previous operative bed in the right level IV. US, the lesion was irregular and hyperechoic with an indistinct margin (Fig. 1B). US-guided fine needle aspiration was performed using a 25-G needle. The second follow-up PET/CT examination, performed 1 year after the first follow-up PET/CT scan, showed a persistent hypermetabolic lesion (SUVmax = 4.3) at the same site (Fig. 1E). On chest CT, the lesion was ovoid, measured 9.8 mm in its maximal longitudinal diameter, and had an indistinct margin from the adjacent sternocleidomastoid muscle (Fig. 1F). However, the lesion seemed to be slightly hyperdense relative to the adjacent sternocleidomastoid muscle (mean attenuation: 89-100 Hounsfield unit) and did not significantly enhance after contrast administration (Fig. 1G). Six months later, US showed a change in the echogenicity of the nodule with no change in size, but a slight change in shape (Fig. 1C). TSK Laboratory, Soja, Japan). The gross specimens were dark-pigmented soft tissue fragments (Fig. 1H). Microscopically, these dark-pigmented specimens were foreign body granulomas that comprised extensive deposits of charcoal and multinucleated giant cells, as well as fibrosis; no tumor cells were detected (Fig. 1I).