biology

Spitz nevus

Spitz nevus is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Spitz nevus rather than just read about it. In short: A Spitz nevus is a benign skin lesion. A type of melanocytic nevus, it affects the epidermis and dermis.

Key takeaways

Spitz nevus belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Spitz nevus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Spitz nevus from memory before moving on to harder problems.

Reference excerpt

A Spitz nevus is a benign skin lesion. A type of melanocytic nevus, it affects the epidermis and dermis. It is also known as an epithelioid and spindle-cell nevus, and misleadingly as a benign juvenile melanoma, and Spitz's juvenile melanoma). The name juvenile melanoma is generally no longer used as it is neither a melanoma, nor does it occur only in children.

Pathophysiology

The cause of Spitz nevi is not yet known. There is an association with sunburn, but causation is not established. Genetic studies of Spitz nevi have shown that most cells have the normal number of chromosomes, however a minority (25%) of cells have been shown to contain extra copies of parts of some chromosomes, such as the short arm of chromosome 11 (11p).

Diagnosis

On histopathology, Spitz nevi characteristically have vertically arranged nests of nevus cells that have both a spindled and an epithelioid morphology. Apoptotic cells may be seen at the dermoepidermal junction. The main histologic differential diagnoses are pigmented spindle cell nevus and melanoma.

Treatment Surgical removal is usually performed, even though it is benign.

Epidemiology Spitz nevi are uncommon. Their annual incidence was estimated in a coastal population of sub-tropical Queensland to be 1.4 cases per 100,000 people. For comparison, the annual incidence of melanoma in the same population, which is high by world standards is 25.4 cases per 100,000 people. Although they are most commonly found on people in their first two decades of life, the age range for people with Spitz nevi is from 6 months to 71 years, with a mean age of 22 years and a median age of 19 years.

Eponym The lesion is named after Sophie Spitz, the pathologist who originally described it in 1948.

See also List of cutaneous conditions List of genes mutated in pigmented cutaneous lesions Melanoma with features of a Spitz nevus

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Spitz nevus

Start with the simplest possible case. Write down what Spitz nevus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Spitz nevus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Spitz nevus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Spitz nevus

In research: Spitz nevus appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Spitz nevus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Spitz nevus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Melanocytic nevi and neoplasms, Rare diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Spitz nevus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Spitz nevus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Spitz nevus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Spitz nevus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Spitz nevus in simple terms?

A Spitz nevus is a benign skin lesion. A type of melanocytic nevus, it affects the epidermis and dermis.

Why does Spitz nevus matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Spitz nevus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Spitz nevus.