Fig. 8.102 Microinvasive cancer: early stromal invasion. Nests of tumor
cells lying within 1 mm from the basal layer of the overlying epithelium.
Dense infiltrate of lymphocytes and plasma cells in the surrounding stroma
(H&E x MP).
invading body of cells is well demarcated and surrounded by a
dense infiltrate of lymphocytes and plasma cells, which charac-
teristically leave a loose, somewhat edematous clear zone free of
inflammatory cells around the invading cell groups.198,199,202,203
The increased amount of eosinophilic cytoplasm is probably
not a sign of improved differentiation but, on the contrary, a
reflection of dedifferentiation enabling a cell to break through
the basement membrane and to proliferate despite the host's
immune response in the surrounding stroma.
This rather characteristic histologic profile usually enables a
pathologist to differentiate between extensions of the abnormal
epithelium into invaginations, noninvasive nests of abnormal
surface epithelium due to tangential sectioning, and truly inva-
sive cells in an early stromal invasion.
M icroinvasive Carcinom a
The depth of invasion in microinvasive carcinoma originally
was determined to be less than 5 mm.204,205 The prognosis of the
disease is most clearly determined by the volume of the tumor.
Thus, the extent of invasion in microinvasion carcinoma should
not be measured in one direction only. Measurements should
Fig. 8.103 Microinvasive cancer: early stromal invasion. Cells
protruding into the surrounding stroma, showing an increased cytoplasmic
volume and a decreased nucleocytoplasmic ratio (H&E x OI).
also encompass the spread of the lesion parallel to the surface
epithelium, analyzed in multiple parallel sections (Fig. 8.104).
This enables a pathologist to get a fairly accurate impression of
the volume of the tumor, which is directly related to the chance
of vascular invasion and thus to prognosis. Measurements
should be made with an ocular micrometer calibrated for each
objective. A practical approach is to measure the diameter of
field of vision for each objective once with a stage micrometer
and to relate these measurements to a specimen under study.82 A
diagnosis of a microinvasive cancer should not be made unless
the entire histologic specimen has been carefully examined. The
presence of tumor tissue in the resection margins of the speci-
men should be precluded in view of the high risk of residual
cancer in patients with conization specimens with tumor tissue
present in the resection margins of the cone. Sedlis and col-
leagues found residual cancer in 12 of 15 patients with tumor
in the resection margins of the conization specimen.206 In about
half of these patients, residual tumor growth in the uterus was
more extensive than in the cone.
The risk of distant spread of a microinvasive carcinoma is
related to the depth of invasion, the lateral extent of the lesion,