Briefly, the tumors have polygonal to elongated cells arranged in a trabecular or alveolar pattern
2): Most part of sternal shield without ornamentation, only region between coxae 3 and 4 bear a small area with alveolar pattern
The heart appeared normal in thoracic radiographs, but the pulmonary vasculature was mildly enlarged, and a marked diffuse alveolar pattern
occurred throughout the lungs.
The alveolar pattern
had a value equal to 0 in all the calves evaluated.
The ICR indicated that any amount of an alveolar pattern
was diagnostic of alveolar RMS, but this resulted in an increase in the incidence of alveolar RMS from a range of 20% to 25% to a range of 40% to 45% of all RMS as compared with earlier studies.
The nasolabial biopsy send for histopathological examination revealed non-cohesive cell aggregates with alveolar pattern
areas with predominantly slit like spaces surrounded by irregular round to oval spindle shaped pleomorphic cells invading surrounding muscle tissue (fig.
In the study by Argani et al, (7) the TFE3-positive PEComas were found in younger patients without evidence of tuberous sclerosis, and the lesions were composed of predominantly epithelioid cells in an alveolar pattern with minimal immunoreactivity for muscle markers.
Microscopically, sections from the appendiceal nodule showed large, epithelioid cells arranged in nested and alveolar patterns (Figure, A through C).
These features included an alveolar pattern
of the tumor nests in a rich stroma background, with clear cell components and a palisading arrangement of the peripheral basal cells.
The "zellballen" pattern is a characteristic feature in many tumors, but in some cases it may be obscured by broad anastomosing bands, an alveolar pattern
, a predominance of round to oval cells, and the presence of giant multinucleated cells.