News & Media


Sep 15, 2021

Why the wait: how long does it take to receive results following a biopsy of a skin lesion?

A biopsy is done so that a sample of skin, in this instance a lesion, can be looked at under a microscope to determine the exact diagnosis. Currently the 3–4-week period between a biopsy and results reflects a range of factors which are outlined below:

Step 1: Processing the mole to make it into slides. This can take a couple of days to a week.

Once the mole is removed it is put in a container with formaldehyde. This is a substance that preserves the skin tissue. It is then sent to the hospital histopathology laboratory where it undergoes processing. On arrival it is booked and assigned a unique laboratory number, this is checked and rechecked throughout the subsequent steps to ensure the correct sample is matched to the correct patient.

First, one of the specially skilled biomedical scientists looks at the whole sample, this is called gross examination. Following a protocol, they select the parts of the sample that need to be submitted for analysis. These are made into blocks using paraffin wax, and thin sections of this are then cut using a tool called a microtome and made into multiple slides. The slides are then stained with dyes; different dyes are used to tell the doctors more about how the cells in the skin are behaving to help them with the diagnosis.

Step 2: Review of the slides by a dermatopathologist. This can take a couple of weeks or more.

The slides are given to a consultant dermatopathologist. This is a doctor who, after finishing five years of medical school, completed training as a junior doctor and then specialised in the examination of different human tissues under a microscope with specific expertise in the diagnosis of skin diseases. This takes at least 11 years to achieve.

Some of the things they are looking for are:

  • The outline of the mole and how the cells forming it interact with the normal tissue
  • Differences in the size and shape of the cells forming the mole and if they are dividing
  • How the cells are organised

It isn’t always clear cut and when there is uncertainty, the consultant dermatopathologist takes additional steps to build up the evidence they analyse before forming an opinion. This may include further stains to be applied to the samples. On occasion they seek the opinion of other colleagues, sometimes in different hospitals around the country, to make sure they come to the most accurate conclusion for every patient. As you can tell ensuring they reach this conclusion takes time, expert judgement, and careful examination of all the skin biopsy sample.

Step 3: Discussion of the patient’s result from their biopsy at a Multi- Disciplinary Team (MDT) meeting. These usually take place once a week.

This entails discussing the findings with other specialists involved in the care of patients with skin cancer, including surgeons, dermatologists, skin cancer nurse specialists and the dermatopathologist. Together they come up with individualised plans for each patient ensuring this meets national guidelines on the best way to diagnose and mange a patient’s skin cancer. These meetings are vital for ensuring there is a clear and holistic plan for each patient.

The results are then communicated back to the patient. If the biopsy taken of the lesion does prove to be a skin cancer the patient, with the full support of the medical team, then undergoes treatment, giving them the best possible chance of a full recovery.

This article was written for the British Association of Dermatologists by Professor Minal Singh, Senior Lecturer and Consultant Dermatologist at The University of Manchester and Elena Georgiakakis, 5th year medical student at Manchester University

Why The Wait?’ poster.

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