Hamartoma

[MudPhud20XX]

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I'm trying to understand Hamartoma based on the categories (hyperplasia, hypertrophy, atrophy, metaplasia, dysplasia) we learn in path in growth adaptation. Hamartoma would be considered as an example of "Dysplasia," right? Can anyone confirm this please?

But I guess hamartoma is different form dyplasia since it looks like the cause of hamartoma is different from dyplasia, right?

Causes of
1) hamartoma: not fully understood (based on wiki)
2) dysplasia: due to stress, reversible with allevaiation of inciting stress (from pathoma)

Many thanks in advance.

 

[Myxedema]

Traditionally, hamartoma is a disorganized tissue. "Disorganized" in this context means presence of tissues normally found within an organ, but in an abnormal architecture. The most common example of an hamartoma is pulmonary hamartoma: It contains all the tissues you can expect to see in a lung, like fat, cartilage, connective tissue, etc., but located in a lesion that is not architecturally continuous with the rest of the organ.
Now, in reality, some people think it is a true neoplasm (a benign mesenchymal tumor), and some people think it is a bridge between neoplasms and congenital malformations. Since this is still controversial, if there is a question about hamartomas, it will not be described using neoplastic terminology.
In summary, if you see "normal" but disorganized tissue = hamartoma. Also, pulmonary hamartoma is worth knowing.

 

[addy]

Traditionally, hamartoma is a disorganized tissue. "Disorganized" in this context means presence of tissues normally found within an organ, but in an abnormal architecture. The most common example of an hamartoma is pulmonary hamartoma: It contains all the tissues you can expect to see in a lung, like fat, cartilage, connective tissue, etc., but located in a lesion that is not architecturally continuous with the rest of the organ.
Now, in reality, some people think it is a true neoplasm (a benign mesenchymal tumor), and some people think it is a bridge between neoplasms and congenital malformations. Since this is still controversial, if there is a question about hamartomas, it will not be described using neoplastic terminology.
In summary, if you see "normal" but disorganized tissue = hamartoma. Also, pulmonary hamartoma is worth knowing.

Thanks for your response. I had this topic last semester and I can't quite remember/find in my notes...what's it called when you have tissue that is foreign to that organ growing inside of it?

 

[Myxedema]

Thanks for your response. I had this topic last semester and I can't quite remember/find in my notes...what's it called when you have tissue that is foreign to that organ growing inside of it?

"Foreign to the organ/location" is ectopic or heterotopic tissue. Gastric tissue in Meckel's diverticulum is an example of this. There is another term, choristoma, which unfortunately leads to a lot of confusion. Is it simply another term for heterotopic tissue? Or, as Robbins puts it, "The designation -oma, connoting a neoplasm, imparts to the heterotopic rest a gravity far beyond its usual trivial significance."? Like hamartoma, there are different opinions.
The way I put them goes like this:
- Normal tissue, normal location, disorganized architecture: Hamartoma. Example: pulmonary hamartoma, presents as solitary nodule, can show popcorn calcification.
- Normal tissue, abnormal location: Choristoma. Example: Pancreatic tissue (i.e. islets of Langerhans) found in stomach wall or liver.

 

[addy]

- Normal tissue, normal location, disorganized architecture: Hamartoma. Example: pulmonary hamartoma, presents as solitary nodule, can show popcorn calcification.
- Normal tissue, abnormal location: Choristoma. Example: Pancreatic tissue (i.e. islets of Langerhans) found in stomach wall or liver.

This is how I made sense of them, too. Thank you, professor!

 

[Apoplexy__]

Normal tissue, normal location, disorganized architecture: Hamartoma. Example: pulmonary hamartoma, presents as solitary nodule, can show popcorn calcification.
- Normal tissue, abnormal location: Choristoma. Example: Pancreatic tissue (i.e. islets of Langerhans) found in stomach wall or liver.

Maybe you could help me with this: I got a question wrong on a test recently that gave the textbook description of Phyllodes tumor histology - "bulbous protrusions of proliferating stroma covered by epithelium" - and hamartoma was also an answer choice. While I understand Phyllodes is the better answer, how would one know that hamartoma is not a feasible choice? My logic was that this tissue was normal, resident to the breast, and benign. The question stem didn't give any other details at all.

 

[Myxedema]

"Bulbous protrusions of proliferating stroma covered by epithelium" You wouldn't expect hamartoma to be proliferating. This is important in real life as well, as proliferation index of neoplasias (often measured by Ki67) tend to be high. Now it would have been better if there were additional descriptors, such as anaplasia, mitotic bodies, etc., but a hamartoma wouldn't be proliferating.

 

[Apoplexy__]

"Bulbous protrusions of proliferating stroma covered by epithelium" You wouldn't expect hamartoma to be proliferating. This is important in real life as well, as proliferation index of neoplasias (often measured by Ki67) tend to be high. Now it would have been better if there were additional descriptors, such as anaplasia, mitotic bodies, etc., but a hamartoma wouldn't be proliferating.

Ah. Great to know, thanks!

 

[ChessMaster3000]

Ah. Great to know, thanks!

kirby, can i ask where you learned the classic histology for phyllodes?

 

[Apoplexy__]

kirby, can i ask where you learned the classic histology for phyllodes?

Haha I meant textbook in a literal sense - Robbins 8e pg. 1092.