PMC4766806_01
52-year-old man with silicone-induced penile sclerosing lipogranuloma. (a) Sagittal T2-weighted image of the penis demonstrates heterogeneous lesion, with ill-defined margins surrounding the penis. The mass (arrowheads) was mainly of low signal intensity on T2-weighted images, a finding suggestive of the presence of fibrous tissue. Corpora cavernosa are intact (long arrow). Image shows normal right testis (asterisk). (b) Transverse apparent diffusion coefficient map (b = 900 mm2/s) shows heterogeneous mass (arrow) surrounding the penile shaft. The lesion appears mainly isointense when compared to the normal corpora cavernosa (long arrow). The apparent diffusion coefficient value of the mass was 1.53 x 10-3 mm2/s (right corpus cavernosum: 1.49 x 10-3 mm2/s; left corpus cavernosum: 1.60 x 10-3 mm2/s). Normal left testis (arrow). Transverse three-dimensional gradient-echo images acquired (c) without and (d) with the application of the magnetization transfers pulse. The magnetization transfer signal of the mass lesion (arrowhead) was qualitatively lower than that of the corpora cavernosa (arrow). The magnetization transfer ratio (in percent) of the lesion was 67%. (e) Time-signal intensity curve of the lesion shows an initial upstroke after which the signal intensity gradually increases in the late contrast-enhanced phase.
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F1
A heterogeneous, ill-defined mass involving the subcutaneous tissues around the penis and extending into the intertesticular and retrotesticular region were detected [Figure 1]. The lesion was asymmetrically Y-shaped with the arms of Y around corpora carvenosae, slightly hyperintense, and extremely hypointense on T1- and T2-weighted images [Figure 1a], respectively when compared to the penile shaft. The mean ADC was 1.53 x 10-3 mm2/s [Figure 1b], similar to that of corpora carvenosae and suggestive of benignity. MTIs showed the very low signal intensity of the mass, with a mean MTR of 67%, suggestive of the presence of macromolecules [Figure 1c and d]. On dynamic imaging, the lesion enhanced strongly and heterogeneously, with an initial upstroke, followed by gradual increase of enhancement in late postcontrast phase [Figure 1e].
52-year-old man with silicone-induced penile sclerosing lipogranuloma. Histopathologic evaluation of the excised tissue reveals vacuoles of variable size in the dermis corresponding to exogeneous substance. Multinucleated giant cells and abundant fibrosis is seen around the vacuoles (Hematoxylin and Eosin stain, magnification x20).
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F2
The diagnosis of sclerosing lipogranuloma was made on histology [Figure 2].