Dermatopathology secrets revealed

February 1, 2007

Kohala Coast, Kona Island, Hawaii - A basic understanding of dermatopathology can improve many dermatologists' biopsy techniques and diagnostic skills, an expert says.

However, most dermatologists receive only a general overview of this topic during their training and may not be aware of some of the working knowledge of diagnostic dermatopathology, he adds.

"Most clinicians and residents view dermatopathology as a means to an end, not a career," says Clay J. Cockerell, M.D., managing director of Cockerell and Associates, Dermpath Diagnostics in Dallas, and past president of the American Academy of Dermatology.

Furthermore, dermatologists exhibit varying levels of understanding regarding what it takes to run a lab and make histologic diagnoses, Dr. Cockerell says.

Clinical correlation

As Dr. Cockerell explains, "Dermatopathology isn't just about what's on the slide - in dermatology, clinical correlation is essential, as many diseases give similar histologic reaction patterns."

He notes one representative case in which a patient presented to her local physician with a history of what the physician believed was a skin rash.

"The physician sent a biopsy sample to a local pathologist for a diagnosis," Dr. Cockerell reports.

The pathologist interpreted the sample as cutaneous lymphoma, and the patient underwent two courses of chemotherapy, he says.

"After each course," Dr. Cockerell says, "the disease remitted but promptly recurred."

Finally, he says the oncologist took the patient to a skin tumor conference for additional recommendations, resulting in a revised diagnosis of lymphomatoid papulosis, which cleared completely after PUVA.

To get better clinical pathological correlation for one's patients, Dr. Cockerell recommends including as much information as is reasonable - and legible - on pathology request forms.

Special problems

Inflammatory lesions pose special problems, he tells Dermatology Times.

When dealing with these lesions, he recommends doing more than one biopsy at different stages of evolution or from different body sites.

Dermatopathologists learn to recognize typical patterns, Dr. Cockerell says, "But who biopsies classic patterns?"

In biopsying suspicious lesions, he adds, "Murphy's Law is paramount; what can go wrong occasionally will."

Therefore, he says, "Always harvest a good piece of tissue and place it in the proper medium, such as 10 percent formalin for routine specimens, Michel's transport media for immunofluorescence (IF) or saline or culturette tube for cultures, and get it to the appropriate lab promptly."

Careful technique

Additionally, Dr. Cockerell says that with respect to biopsy technique, "Punches of broad lesions, especially possible melanoma, may give artifactually negative results."

For example, he says that a lesion's darkest area might be an area of hemorrhage, a zone of heavy melanin or an associated solar lentigo or seborrheic keratosis.

"If one punches," Dr. Cockerell adds, "make it a big punch - at least 5 mm - or punch out (excise) the entire lesion."

Multiple small punches provide a shotgun rather than panoramic view, he cautions.

Similarly, he says, in diagnosing melanocytic lesions, grading of dysplastic nevi has proven problematic.