PMC6350031_01
A ring-enhanced lesion in the left medial temporal lobe (A), accompanied by edema around the lesion (B). The inside appears hyper-intense on diffusion-weighted imaging (C) and hypo-intense on the apparent diffusion coefficient map (D). A week after beginning antibiotic therapy (day 7), the lesion has reduced in size slightly (E) and the edematous area around the lesion has decreased (F).
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F1
Screening brain MR imaging (day-3) with contrast enhancement then revealed a 1.3-cm ring-enhancing mass lesion in the left medial temporal lobe (Figs. 1A and 1B). The internal part of the enhanced rim appeared hyper-intense on DWI (Fig. 1C) and hypo-intense on an apparent diffusion coefficient (ADC) map (Fig. 1D). After 1 week, MR images suggested the efficacy of antibiotics (Figs. 1E and 1F).
Summarized clinical course. Each symbol indicates clinical events as follows: closed triangle, first-line chemotherapy for lung cancer; open triangle, administration of durvalumab (MEDI4736); star, chemotherapy for the left femoral metastasis; and double circle, surgical resection of the left temporal lesion. Time courses of CRP (mg/dl) and CYFRA (ng/ml) are also shown. Data before durvalumab are unavailable because previous treatments were provided at another hospital. MEPM: meropenem, VCM: vancomycin, CFPM: cefepime, RT: radiotherapy for the left femoral metastasis. Oral antibiotics consisted of levofloxacin and metronidazole.
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F2
The clinical course is shown in Fig. 2.
Post-contrast MRI on day 119 demonstrates an enlarged lesion (A), and the contents show heterogeneous hyper- and hypo-intensity on DWI (B).
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F3
However, the left temporal lobe lesion gradually enlarged, reaching 1.6 cm on day 78, 2.2 cm on day 106, and 2.6 cm on day 119 (Fig. 3). Imaging characteristics changed from a single cyst to multiple cysts (Fig. 3).
Operative view of the lesion containing whitish, pus-like fluid (arrowheads) (A). Tumor shows a slightly grayish appearance (arrows) (B).
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F4
The lesion was slightly harder than the brain parenchyma and contained whitish creamy fluid (Fig. 4).
Hematoxylin and eosin staining of tumor sections. Pathological findings indicate metastatic squamous cell carcinoma. The tumor cells are arranged in a trabecular pattern with focal squamous differentiation. Large tumor cells contain highly pleomorphic and hyperchromatic nuclei (A). Microscopic examination of the content smear shows Gram-positive bacilli (arrow) (B).
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F5
The pathological diagnosis was metastatic squamous cell carcinoma (Fig. 5A). In addition, smear preparation of the whitish creamy fluid detected Gram-positive bacilli (Fig. 5B).