Microscopic histopathological analyses of hematoxylin and eosin stained FHI tumor tissues consistently reveal three very different component zones in virtually all cases: 1) haphazardly arranged, intersecting bundles of bland fibroblast-like/myofibroblast-like cells; 2) mature adipose (i.e. fat) tissue; and 3) highly vascular, myxoid (i.e. connective tissue appearing more blue or purple than normal connective) nodules of primitive-appearing spindled-shaped to star-shaped cells. Chronic inflammatory cell (e.g. lymphocytes, macrophages, and plasma cells) aggregates are commonly present in these lesion. The relative proportion of fibroblast/myofibroblast, adipose tissue, and myxoid zones commonly vary from case to case.Earlier Immunohistochemical analyses of FHI tumor tissues in a small number of cases have given varying results. A more recent and larger study reported that 75% of tested cases showed variable expression of smooth muscle actin proteins by the cells located primarily in fibroblast/myofibroblast zones and occasionally by the cells located in myxoid zones; the S100 protein was expressed by the fat cells of the adipose tissue zone in all cases; CD34 protein was expressed by the cells in myxoid and fibroblast/myofibroblast zones in all cases; and cells expressing the desmin protein were not detected in any case. A smaller, more recent study also found that 8 of 13 FHI cases had tumor cells in the fibroblast/myofibrobalast zone that expressed smooth-muscle actin protein, 6 of 8 cases had tumor cells in the myxoid zone that expressed the CD34 protein, and 7 of 7 cases had tumor cells in the adipose tissue zone express the S100 protein.
The vacuoles are strongly reactive for dystrophin and lysosome associated membrane protein 2 (LAMP2). Membrane bound vacuoles and balls of dense material under the basal lamina are present. Deposition of the C5b-9 complement attack complex, subsarcolemmal deposition of calcium and expression of MHC1 complex also occur.On electron microscopy characteristic balls of dense material are commonly seen. The vacuoles may contain remains of mitochondria, membrane whorls and calcium apatite crystals. Diagnosis
The diagnosis can be established by muscle biopsy. Investigations
The serum creatinine is raised. Differential diagnosis
Acid maltase deficiency
Danon disease

Treatment
History
This disorder was described in 1988 by Kalimo et al in Finland in three brothers. The same condition affected their maternal grandfather and great-uncle. References


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