Saturday, March 13, 2021

Metastatic Scalene Node Case File

Posted By: Medical Group - 3/13/2021 Post Author : Medical Group Post Date : Saturday, March 13, 2021 Post Time : 3/13/2021
Metastatic Scalene Node Case File
Eugene C. Toy, MD, Lawrence M. Ross, MD, PhD, Han Zhang, MD, Cristo Papasakelariou, MD, FACOG

CASE 39
A 67-year-old man is noted to be coughing up bright red blood for a period of 1 week. He denies exposure to tuberculosis but has smoked one pack of cigarettes per day for 30 years. On examination, his lungs are clear. Palpation of the supraclavicular regions shows a hard nontender irregular mass on the left side.

 What is the most likely diagnosis?
 What is the anatomical explanation for this particular mass?


ANSWER TO CASE 39:
Metastatic Scalene Node

Summary: A 67-year-old man who has smoked cigarettes for 30 years has a 1-week history of hemoptysis. Palpation of the supraclavicular regions shows a hard nontender irregular mass on the left side.

• Most likely diagnosis: Lung cancer with a left-side supraclavicular metastatic
node
• Anatomical explanation for this particular mass: Lymphatic drainage through the thoracic duct to the left brachiocephalic vein


CLINICAL CORRELATION
This smoker complains of hemoptysis, the expectoration of bright red blood, for 1 week. This is very suspicious for lung cancer. In addition, he has a hard irregular mass in the left supraclavicular region. This is most likely malignant metastasis to lymph nodes in this area. Because lymph draining the abdomen, thorax, and lower extremities is directed through the thoracic duct into the left subclavian vein, the most common location of supraclavicular node involvement is the left side.


APPROACH TO:
The Neck: Lymphatics

OBJECTIVES
1. Be able to describe general patterns of lymphatic drainage in the body
2. Be able to distinguish lymphatic flow through the supraclavicular nodes from flow through other nodes in the neck

DEFINITIONS
HEMOPTYSIS: Coughing up blood

PALPATION: Technique of physical examination that uses the hands or fingers to sense involuntary muscle tightening due to pain, or masses

METASTASIS: Spread of disease from one part of the body to another, the term generally used to describe the spread of cancer cells


DISCUSSION
The lymphatic system complements the venous system as a pathway for return of serum constituents to the heart. Blood flows from the lungs to the periphery by the pumping action of the heart. In the closed vascular system, the venous system forms

from the capillaries, the vessels with the smallest diameter. The blood is drained into increasingly large veins as it is transported back to the heart and lungs. However, not all constituents of the extracellular fluid are captured into the venous system. A secondary pathway is through the lymphatic system. These fine vessels form from plexuses in tissues and, like veins, form vessels of increasing diameter. Unlike veins, however, the lymphatic vessels are not continuous channels. Instead, they are interrupted by lymph nodes, which contain dense aggregations of white blood cells.

In general, lymphatics from below the diaphragm on both sides of the body drain into the cisterna chyli and then to the thoracic duct. This is a particularly important pathway for fat droplets that are absorbed from the gastrointestinal tract after a meal. The thoracic duct ascends in the posterior mediastinum to drain into the venous system at the junction between the left subclavian and internal jugular veins. Above the diaphragm, including the head and neck, lymphatics on the left side also drain into the thoracic duct. On the right side, the vessels drain into the smaller right lymphatic duct, which drains variably into the right subclavian vein.

In the neck, lymphatic vessels flow from superficial to deep, paralleling the major veins. Several clusters of lymph nodes have been distinguished and divided into superficial and deep groups. In general, flow is from superior to inferior and from superficial to deep. However, the inferior deep group, which lies along the inferior portion of the internal jugular and subclavian veins, also drains the upper extremity, thorax, and abdomen.

The lymphatic system is important for understanding the spread of cancer (Figure 39-1). Unlike veins, the contractile force of the heart exerts no hydrostatic pressure in lymphatic vessels. Lymph moves by compression from

Lymphatics of the neck anatomy

Figure 39-1. Lymphatics of the neck. (Reproduced, with permission, from Lindner HH. Clinical Anatomy. East Norwalk, CT: Appleton & Lange, 1989:156.)

surrounding tissues. Few lymphatic vessels have valves, so flow is highly variable. Transformed cells from one tissue can migrate through the lymphatics to adjacent tissues. Tumor cells will frequently proliferate within lymph nodes and cause the nodes to enlarge. In the neck, the supraclavicular nodes are frequently referred to as the sentinel nodes because their enlargement can be the first sign of cancer originating in the thorax or abdomen.


COMPREHENSION QUESTIONS

39.1 A 57-year-old man is diagnosed with colon cancer. He is noted to have a probable metastatic mass in the neck at the thoracic duct. Where is the metastasis likely to be located?
    A. Right supraclavicular region
    B. Right subclavicular region
    C. Left supraclavicular region
    D. Left subclavicular area
39.2 A 65-year-old woman is noted to have cancer of the vulva. Metastasis of the cancer to the lymph nodes in the femoral triangle is noted. Which of the following best describes the location of the lymph nodes?
    A. Immediately lateral to the femoral nerve
    B. Immediately medial to the femoral nerve
    C. Immediately medial to the femoral artery
    D. Immediately medial to the femoral vein
    E. Immediately lateral to the femoral vein
39.3 Which mechanism propels lymph through the lymphatic vessels?
    A. Cardiac contractility
    B. Gravity
    C. Peristalsis
    D. Compression


ANSWERS
39.1 C. The thoracic duct drains into the left subclavian vein. Malignant metastasis is often diverted to the supraclavicular nodes, where it proliferates.
39.2 D. The relations of the structures in the groin can be recalled by the mnemonic NAVEL: Nerve, Artery, Vein, Empty space, Lymph node.
39.3 D. Compression is the primary means for lymph movement through the lymphatic vessels.


ANATOMY PEARL
 Lymphatic vessels are not continuous channels but are interrupted by lymph nodes, which contain dense aggregations of white blood cells (lymphocytes).
 In general, lymphatics from below the diaphragm on both sides of the body drain into the cisterna chyli and then to the thoracic duct.
 The lymph ascends in the posterior mediastinum to drain into the venous system at the junction between the left brachiocephalic and internal jugular veins.

References

Gilroy AM, MacPherson BR, Ross LM. Atlas of Anatomy, 2nd ed. New York, NY: Thieme Medical Publishers; 2012:128−129, 614. 

Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy, 7th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2014:117−118, 125, 169. 

Netter FH. Atlas of Human Anatomy, 6th ed. Philadelphia, PA: Saunders; 2014: plates 74, 205.

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