Answer: Diagnosis - Amyloidosis.

The photo is a portion of a subcutaneous fat biopsy showing
amyloid deposition along the surface of lipocyte
membranes i.e. amyloid rings

Click here to review the whole case.: It is important to get an adequate sample of subcutaneous fat in
these biopsies. i.e. not just the tiny bit that is usually obtained
with the punch biopsy alone.
Performing a labial salivary gland biopsy, in addition,
increases the sensitivity of detection.