Table 1.
Clinical and pathologic features of AMFB and AA.
| AMFB | AA | |
|---|---|---|
| Clinical features | ||
| Age (years) | 16 – 86 (Median 45) | 16 – 70 (Median 37) |
| Size (cm) | < 5 (0.5 – 23) | >5 (1-60) |
| Location | Female pelvis and perineum: predominantly vulvar/vaginal | Female pelvis and perineum |
| Onset | 1 month to 8 years | 1 month – 5 years |
| Predominantly 1-2 years | Predominantly < 1 year | |
| Recurrence | None reported | 33-72% |
| Pathology | ||
| Low-power features | Well-defined | Infiltrative |
| No entrapment of mucosal glands or nerve bundles | Entrapped mucosal glands and nerve bundles | |
| Alternating hypocellular and hypercellular areas | Stromal cells distributed throughout | |
| Vasculature | Abundant thin-walled vessels, mostly capillary-like | Small to medium-sized vessels, mostly thick-walled or hyalinized |
| Stromal cells | Abundant | Low cellularity |
| Spindle, plump spindle, or oval | Thin delicate spindle or stellate | |
| Perivascular aggregation | Mitotic figures typically absent | |
| Mitotic figures typically absent | ||
| Stroma | Mucin-poor, containing delicate, wavy collagen fiber | Myxoid, hyaluronic-acid rich |
| Immunostaining | ||
| Desmin | Positive (50-60%) | Positive (Up to 73%) |
| α –SMA | Negative (positive in up to 15%) | Positive |
| S-100 | Negative | Negative |
| Vimentin | Positive | Positive |
| Estrogen receptor | Positive | Positive |
| Progesterone receptor | Positive | Positive |