AssessmentsCardiac and vascular tumors: Pathology review
USMLE® Step 1 style questions USMLE
A 15-year-old boy is being evaluated in the clinic after passing out in school during physical activity class. Medical history is significant for hyperactivity and behavioral problems since childhood. He often gets into fights, talks back to his teachers and has low performance in school. A recent IQ test evaluation was 71. Physical examination reveals a cardiac murmur. An echo is obtained and reveals a cardiac mass. Which of the following additional findings is most likely to be found on further evaluation of this patient?
Two people came to the clinic one day. Kara is a 66 year old woman who came to the clinic after noticing gradually developing left arm swelling and redness over the past 3 months. Physical examination reveals a tender purplish lesion along the left armpit. She has a history of hypertension, diabetes, and breast cancer that was treated 10 years ago with a modified radical mastectomy and radiation therapy.
Klay is a healthy 1 year old infant brought by his parents due to a rapidly growing “red bump” on his face. He has no history of trauma, and the lesion didn’t appear elsewhere. Physical examination reveals a raised, bright red nodule on the left side of his face and no other abnormal findings.
Now, both Kara and Klay have vascular tumors. There are many types so it’s best to classify them into benign and malignant tumors. Starting with the most common benign vascular tumor in children; the strawberry hemangioma, where Hemangioma means a benign tumor of the blood vessels. A strawberry hemangioma appears as a superficial, bright red skin lesion that looks kind of like a strawberry, and it commonly affects the face. Histologically, these lesions are confined to the epidermis. Now a typical strawberry hemangioma develops in infancy and grows pretty fast, but fortunately, it goes away on its own by 5 to 10 years of age. So in terms of management, exams like to bring up a very concerned parent, but the correct answer will almost always be to reassure the parent that the lesion will regress without treatment.
Now, a related disorder is cherry hemangioma, which is the most common benign vascular tumor in adults. This tumor appears dark red, like a cherry. Histologically, this lesion extends to the superficial papillary dermis, so they reach much deeper than strawberry hemangiomas. These tumors increase in frequency with age, and unlike strawberry hemangiomas, they do not regress spontaneously.
Cavernous hemangiomas are soft, bluish lesions, and unlike strawberry and cherry hemangiomas, they are usually seated in the deep dermis. The word “cavernous” means cavern-like. So it’s not surprising that histologically, these appear as large, endothelium-lined spaces filled with red blood cells. Cavernous hemangiomas can also be located in organs like the liver, spleen or even the brain. Also, Von-Hippel Lindau syndrome is an autosomal dominant condition that causes numerous tumors and cysts throughout the body, one of these being cavernous hemangiomas of the cerebellum and retina. Look for a history of bilateral pheochromocytoma or renal cell carcinoma.
The next tumor is cystic hygroma, or a cavernous lymphangioma. It’s a benign tumor of the lymphatic vessels that typically arises in the neck, and is associated with both Down and Turner syndrome. Histologically, this tumor is made of an endothelial lining, but the difference between it and hemangiomas is the absence of red blood cells, because lymphatic vessels have lymphatic fluid in them, not blood
Next up we have pyogenic granuloma, which is the biggest misnomer in medicine. First, it does not produce pus, and histologically, it’s not a granuloma. Instead, this is a benign, polypoid or dome-shaped hemangioma that can ulcerate and bleed. Histologically, the tumor shows lobules made of proliferating capillary and edema, which makes it look like granulation tissue. Board exams will often give you risk factors, such as a history of trauma to the area, or pregnancy, especially in the first trimester.
Next are glomus tumors. These arise in the glomus bodies which are small arteriovenous shunts located in the dermis. They help regulate body temperature by shunting blood away from the skin in cold temperatures, and to the skin when it’s hot. A glomus tumor usually arises from the smooth muscle cells in the glomus bodies and they are painful, bluish-reddish tumors most commonly found under the fingernails. An important differential diagnosis is subungual melanoma, which appears similarly, but the difference is the presence of melanin-pigmented cells in histology. So it’s important to get a biopsy!
The next two tumors are associated with HIV. There’s bacillary angiomatosis, which is benign, and Kaposi sarcoma, which is malignant. Bacillary angiomatosis is technically not a tumor; it’s an infection caused by the gram negative bacillus, Bartonella henselae. It’s thought that the bacteria enters the intravascular compartment, and releases angiogenic factors that stimulate benign endothelial cell proliferation. Kaposi sarcoma on the other hand is a malignancy of the endothelial and smooth muscle cells caused by human herpesvirus 8, or HHV-8, or by HIV.
It’s still unknown exactly how these viruses cause malignancy. Now, both conditions appear as red-violet papules on the skin. Kaposi sarcoma also tends to affect the buccal mucosa as well as the gastrointestinal and respiratory tracts. So beware of questions that pose Kaposi sarcoma as a case of GI bleeding or hemoptysis. The best way to differentiate the two is microscopically. Bacillary angiomatosis shows gram negative bacilli using Warthin-Starry stain, as well as a neutrophilic infiltrate. On the other hand, Kaposi sarcoma shows spindle shaped tumor cells along with a lymphocytic infiltrate.
Okay, another malignant tumor of the blood vessels is angiosarcoma, which is a cancer of the endothelial lining of the blood vessels. They are more common in older people and affect sun-exposed areas like the head,and neck. If the person has a history of radiation therapy, like for breast cancer, they can also develop. A specific type is hepatic angiosarcoma which is linked to chronic exposure to arsenic in pesticides, polyvinyl chloride, or PVC, a plastic commonly used in industry, and thorotrast, an old contrast medium. A helpful clue is that hepatic angiosarcoma cells express CD31, also called PECAM1, which is normally expressed on the surface of endothelial cells and acts as a binding point for leukocytes. However, in angiosarcoma, CD31 promotes angiogenesis, which is how these tumors develop. This is a way your exams can connect this pathology with normal physiology.
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