NEOPLASIA II

Slide 33 [WinLab] [Mac] [WinHome]

Uterus: Leiomyoma

This slide represents a portion of myometrium from a 48-year-old woman. Grossly, the myometrium was distorted by numerous circumscribed nodules ranging in size from 2 to 6 centimeters. As you inspect this slide under scanning power, you will note a roughly circular area that stains more deeply than the surrounding myometrium. This area is not encapsulated, but seems to be separated from the adjacent myometrium along at least part of its circumference.

• Under the scanning power of your microscope, note that this circumscribed area is rather more densely cellular, with a higher concentration of nuclei and hence a somewhat bluer hue. This more cellular area represents the leiomyoma.

• Note the structure of the normal myometrium -- interlacing bundles of spindle shaped cells.

• Note that the neoplasm is also composed of interlacing bundles of spindle shaped cells. While not actually encapsulated, the nodule is easily distinguished from its surroundings.

• Compare the nuclei in the nodule with those in the normal myometrium. Their features are characteristic of a benign neoplasm.

• How would a malignancy of this same tissue differ cytologically form this specimen?

• These lesions are commonly known as uterine "fibroids." Why is leiomyoma a better name? What is the name of the malignant counterpart?

• How do uterine leiomyomas present clinically?

• Where else might you find a leiomyoma?

Slide 34 [WinLab] [Mac] [WinHome]

Colon: Lipoma

This lesion was found incidentally at autopsy of a 56-year-old man and had nothing whatever to do with his demise. The lesion was a large yellow nodule beneath an intact mucosa.

• Under the scanning power of your microscope note the intact mucosa overlying the lesion. The muscle wall of the colon is distorted and attenuated by the presence of the lesion.

• Closer inspection of the lesion itself reveals nothing more than histologically mature adipose tissue. Do you think you could distinguish the cells of this lipoma from those of normal adipose tissue given just a restricted field of view? What features would lead you to believe that this was a neoplasm at all?

• What would be the histologic appearance of a malignant neoplasm of adipose tissue? What would it be called?

• What is a more typical clinical expression of lipoma? What is the biological significance of a lipoma?

Slide 35 [WinLab] [Mac] [WinHome]

Soft Tissue: Leiomyosarcoma

This lesion actually came from the soft tissue of the scalp of an elderly male patient. The origin of the neoplasm was presumably a vascular wall (this was apparent in other sections of the neoplasm). A neoplasm such as this could have arisen in any other tissue containing smooth muscle, such as myometrium.

• Scanning power inspection of the section reveals that it consists almost entirely of neoplasm with only a shell of overlying connective tissue.

• Closer inspection reveals that the neoplasm consists of interlacing bundles of spindle shaped cells in a focally collagenous background. Compare this to the neoplasm in Slide 33 [WinLab] [Mac] [WinHome], noting the features in this neoplasm that would allow you to call it malignant.

Slide 36 [WinLab] [Mac] [WinHome]

Soft tissue of lower extremity: Liposarcoma

This section represents a bulky neoplasm from the thigh of a 49-year-old woman.

• Scanning power inspection of the section reveals a portion of a light staining nodular lesion bordered by a more deeply staining tissue.

• Close inspection reveals a rather cellular neoplasm, lobules of which extend into adjacent, distorted skeletal muscle. The neoplasm itself is extremely cellular and has a finely vascular background.

• This lesion is the malignant counterpart of the lesion seen in Slide 34 and a comparison of the two is useful. Some of the cells in this lesion can be identified as adipocytes of more or less the usual sort. Other cells are rather peculiar cells with multiple cytoplasmic lipid droplets indenting the nucleus. Still others are rather nondescript appearing, less well differentiated cells. The cellularity, nuclear pleomorphism, and invasiveness of this neoplasm identify it as malignant. The mitotic rate in this neoplasm is undoubtedly higher than that in the benign counterpart, but ascertaining this would take more time than you have.

• Where else might you expect to find a liposarcoma?

• You have now seen a leiomyosarcoma and a liposarcoma. What would a malignant neoplasm arising from cartilage be called? From bone?

• Generally speaking, when you’ve identified a malignant neoplasm in a tissue, how do you go about deciding whether it’s primary there or metastatic?

Slide 37 [WinLab] [Mac] [WinHome]

Liver: Metastatic Adenocarcinoma

This specimen came from a man who had a colonic adenocarcinoma resected three years earlier. At autopsy his liver was studded with multiple nodules.

• Under scanning power note the nodular lesions replacing and compressing hepatic parenchyma.

• Closer inspection reveals the nodules to consist of proliferating epithelial cells forming trabecular and ductal or glandular spaces.

• What cytologic features identify the neoplasm as malignant?

• What is a justification for calling this adenocarcinoma?

• Can you account for the pink and blue staining granular material in the center of the nodules?

• In this case, the neoplasm in the liver is metastatic, having originated from a lesion very similar to that shown to you in Slide 31 [WinLab] [Mac] [WinHome]. Can you imagine an adenocarcinoma primary in liver?

Slide 38 [WinLab] [Mac] [WinHome]

Lymph Node: Metastatic Squamous Cell Carcinoma

These lymph nodes came from the neck of a 74-year-old man.

• Scanning power examination of this section will show one more or less normal node and a second node partly replaced by a pink nodule.

• Under a higher power, the nodule is rather easily identified as consisting of epithelial cells in a fibrous background. What are the cytologic features that allow you to identify this epithelial population as malignant?

• How do you know that this lesion is metastatic rather than primary?

• What histologic features allow you to identify this neoplasm as a squamous cell carcinoma?

• Where do you suppose the primary was and what might you guess about the clinical background of the patient?

Slide 39 [WinLab] [Mac] [WinHome]

Ovary: Teratoma

This specimen came from an ovarian mass found on routine pelvic examination in a 26-year-old woman. This slide is presented to you as an example of a neoplasm of “multi-potential” sort, i.e., differentiating in diverse directions with tissue elements representing various layers of the embryo.

• Imagine a spherical neoplasm expanding within the ovary and compressing the residual normal ovarian tissue into a thin rim. This slide represents multiple sections from the lesion and overlying ovary. Along the convex surface of one of the sections at least, you may be able to identify compressed ovarian stroma, a couple of follicles, and a patch of ova. See how many different tissue elements you can identify in this teratoma. The skin-like elements dominate (hence the somewhat imprecise term “dermoid”) but try to identify all of the other elements present.

• What is the clinical significance of a teratoma having this histologic appearance?

Slide 40 [WinLab] [Mac] [WinHome]

Lung: Hamartoma

This nodule was excised from the lung of an asymptomatic woman. The nodular lesion was found on a routine chest x-ray.

• There is practically no normal tissue present in this specimen, perhaps a few distorted alveoli along the surface.

• The lump is basically a jumble of perfectly well differentiated hyaline cartilage and respiratory type epithelium with a bit of interspersed connective tissue.

• A lesion of this sort is currently viewed as a hamartoma, a mass of disorganized but mature tissue indigenous to the site. Hamartomas are not viewed as neoplasms, but rather as areas of aberrant differentiation that make lumps and bumps.

• Another kind of non-neoplastic lump is a choristoma, a nest of histologically mature tissue in an ectopic location, e.g., a lump of pancreatic tissue in the bowel wall.