Thin calcific plaques and their impression at the surface of the inside of the capsule confirm the onset of mineralization (calcification) at the prosthetic interface. The capsular tissue is nearly acellular and cut sections exhibit evidence of minimal inflammatory activity confirming that the inflammatory process had subsided long before. implant removal and that, for practical purposes, the capsular material was not viable tissue (onset of necrosis). The external side 'of the capsule has a large amount of skeletal muscle tenaciously attached. This material is oil-infiltrated and there is evidence of deep inflammation. The amount and the position of this tissue suggest a difficult and laborious explantation with an implant capsule firmly adhering to muscle over an area of at least 20 sq cm. This residual muscle tissue constitutes a reference point for the orientation of the capsule. Residual fibrofatty breast tissue adheres to the opposite pole of the sacular capsule indicating that the capsule simultaneously contacted both the breast gland and the chest muscles. On that basis, it appears that the implant did not lie exclusively within a subrnuscular pocket. Thickness measurements of the. hyalinized zone of the capsule vary widely from point-to-point. The thinnest is approximately 0.1 mm adjacent to fenestrations and the thickest parts exceed 7 mm near the equator of the capsule, the average being 5 mm. Focal discolouration and embedded optically-dense material are visible with transillumination and confirm loci of accumulated hemosiderin and coloured debris.
The small separate part has the same characteristics as the larger portion and its thickness is nearly 5 mm in one part, the average being 4 mm. This part is nodular and focally hemosiderin-laden. Both sides of the tissue coupon show evidence of long term contact with prosthetic material. On that basis, it would appear that this tissue does not originate from the capsule itself but was instead a partition within the gel-flooded space. Its presentation is consistent with pannus or a projection of capsule which separated two loci of gel-infiltrated material.
The gross physical characteristics of the capsule exhibit features which are not frequently encountered in prosthetic capsules surrounding implants made after 1990. These distinctive features are shown graphically in the illustrations of Appendix C. The most remarkable include the large amount of entrapped mobile silicone-based material and the complex multi-compartment character of the capsule with similarities to an abscess divided by internal septa into multiple compartments.