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Ultrastructural studies of gastrointestinal stromal tumors.

Park SH, Kim MK, Kim H, Song BJ, Chi JG - J. Korean Med. Sci. (2004)

Bottom Line: Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT.ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments.Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Seoul National University, College of Medicine, Seoul, Korea. shparknp@plaza.snu.ac.kr

ABSTRACT
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract (GIT). Although interstitial cells of Cajal has been suggested as origin of this tumor, the cytological and ultrastructural features of GISTs are heterogeneous and unclear. A total 10 cases of normal gastrointestinal tissue (control), 13 GISTs of the stomach (8), small intestine (3), mesocolon (1) and liver (1), and 2 gastrointestinal autonomic nervous tumor (GANT) of small intestine were ultrastructurally studied. Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT. ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments. The GISTs and GANTs had overlapping ultrastructures. The most common and important ultrastructural features of GISTs were rich villous cytoplasmic processes, dispersed intermediate filaments and abundant SER, and those of GANTs were neurosecretory granules and skenoid fibers. Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions. Our study suggested that ultrastructural analysis gives much information to investigate lineage differentiation of neoplastic cells and make a differential diagnosis of these tumors from other mesenchymal tumors and between GISTs and GANTs.

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(A) Spindle cell GIST also shows cytoplasmic processes but do not have much villous processes. The neoplastic cells have a nuclear pseudoinclusion and rich organelles including electron dense lysosomal granules. There are hemidesmosome-like junctions (arrowheads) as well as a few gap junctions (arrow). Incontinuous external lamina is seen. (B) Ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments are seen (arrows) (uranyl acetate and lead citrate stain, bar: 2 µm, A: ×5,000, B: ×6,000).
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Figure 6: (A) Spindle cell GIST also shows cytoplasmic processes but do not have much villous processes. The neoplastic cells have a nuclear pseudoinclusion and rich organelles including electron dense lysosomal granules. There are hemidesmosome-like junctions (arrowheads) as well as a few gap junctions (arrow). Incontinuous external lamina is seen. (B) Ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments are seen (arrows) (uranyl acetate and lead citrate stain, bar: 2 µm, A: ×5,000, B: ×6,000).

Mentions: Ultrastructurally, the neoplastic cells were polygonal or elongated in appearance. The polygonal cells usually had rich interdigitating cytoplasmic processes and most of them were villous (filopodia-like) (Fig. 5). However spindle shaped neoplastic cells did not have well developed villous processes (Fig. 6). The nuclei were oval to irregularly elongated and generally heterochromatic, but some nuclei were exceptionally euchromatic (Fig. 5, 6). The tumor cells were closely apposed except the areas having intercellular collagenous stroma. There were also abundant wavy intermediate filaments, which were generally dispersed in the cytoplasm. The cytoplasmic organelles were abundant, smooth and rough endoplasmic reticulum, mitochondria, lysosomes and Golgi apparatus. There were desmosome or hemidesmosome-like junctions as well as a few gap junctions (Fig. 6) in 2 cases of gastric GISTs. A discrete external lamina was usually absent but incontinuous external lamina material was present in half of the GISTs (Fig. 6). Caveolae or pinocytotic vesicles were rarely seen. A case with focal immunohistochemical smooth muscle differentiation showed ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments (Fig. 6). Small round dense core neurosecretory granules were observed in GANTs, measuring 40-150 nm in diameter (Fig. 7), but GISTs also had electron dense granules, favor lysosomes, which could be confused with neurosecretory granules. No definite synaptic junction, synaptic vesicles or microtubles were found in GANTs. In all two cases of GANTs, skenoid fibers were characteristically present (Fig. 8).


Ultrastructural studies of gastrointestinal stromal tumors.

Park SH, Kim MK, Kim H, Song BJ, Chi JG - J. Korean Med. Sci. (2004)

(A) Spindle cell GIST also shows cytoplasmic processes but do not have much villous processes. The neoplastic cells have a nuclear pseudoinclusion and rich organelles including electron dense lysosomal granules. There are hemidesmosome-like junctions (arrowheads) as well as a few gap junctions (arrow). Incontinuous external lamina is seen. (B) Ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments are seen (arrows) (uranyl acetate and lead citrate stain, bar: 2 µm, A: ×5,000, B: ×6,000).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2822305&req=5

Figure 6: (A) Spindle cell GIST also shows cytoplasmic processes but do not have much villous processes. The neoplastic cells have a nuclear pseudoinclusion and rich organelles including electron dense lysosomal granules. There are hemidesmosome-like junctions (arrowheads) as well as a few gap junctions (arrow). Incontinuous external lamina is seen. (B) Ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments are seen (arrows) (uranyl acetate and lead citrate stain, bar: 2 µm, A: ×5,000, B: ×6,000).
Mentions: Ultrastructurally, the neoplastic cells were polygonal or elongated in appearance. The polygonal cells usually had rich interdigitating cytoplasmic processes and most of them were villous (filopodia-like) (Fig. 5). However spindle shaped neoplastic cells did not have well developed villous processes (Fig. 6). The nuclei were oval to irregularly elongated and generally heterochromatic, but some nuclei were exceptionally euchromatic (Fig. 5, 6). The tumor cells were closely apposed except the areas having intercellular collagenous stroma. There were also abundant wavy intermediate filaments, which were generally dispersed in the cytoplasm. The cytoplasmic organelles were abundant, smooth and rough endoplasmic reticulum, mitochondria, lysosomes and Golgi apparatus. There were desmosome or hemidesmosome-like junctions as well as a few gap junctions (Fig. 6) in 2 cases of gastric GISTs. A discrete external lamina was usually absent but incontinuous external lamina material was present in half of the GISTs (Fig. 6). Caveolae or pinocytotic vesicles were rarely seen. A case with focal immunohistochemical smooth muscle differentiation showed ultrastructual differentiation toward smooth muscle, such as cytoplasmic myofilaments (Fig. 6). Small round dense core neurosecretory granules were observed in GANTs, measuring 40-150 nm in diameter (Fig. 7), but GISTs also had electron dense granules, favor lysosomes, which could be confused with neurosecretory granules. No definite synaptic junction, synaptic vesicles or microtubles were found in GANTs. In all two cases of GANTs, skenoid fibers were characteristically present (Fig. 8).

Bottom Line: Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT.ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments.Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Seoul National University, College of Medicine, Seoul, Korea. shparknp@plaza.snu.ac.kr

ABSTRACT
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract (GIT). Although interstitial cells of Cajal has been suggested as origin of this tumor, the cytological and ultrastructural features of GISTs are heterogeneous and unclear. A total 10 cases of normal gastrointestinal tissue (control), 13 GISTs of the stomach (8), small intestine (3), mesocolon (1) and liver (1), and 2 gastrointestinal autonomic nervous tumor (GANT) of small intestine were ultrastructurally studied. Normal interstitial cells of Cajal (ICC) were abundantly present around the myenteric plexuses or individually scattered through the wall of GIT. ICC was characterized by slender cytoplasmic processes, well-developed endoplasmic reticulum (ER), mitochondria, Golgi apparatus, caveolae and intermediate filaments. The GISTs and GANTs had overlapping ultrastructures. The most common and important ultrastructural features of GISTs were rich villous cytoplasmic processes, dispersed intermediate filaments and abundant SER, and those of GANTs were neurosecretory granules and skenoid fibers. Compared with ICC, the GISTs and GANTs had remarkably reduced caveolae and gap junctions. Our study suggested that ultrastructural analysis gives much information to investigate lineage differentiation of neoplastic cells and make a differential diagnosis of these tumors from other mesenchymal tumors and between GISTs and GANTs.

Show MeSH
Related in: MedlinePlus