If you’ve ever received a pathology report and felt like you were reading a foreign language — you’re not alone. Terms like atypical basaloid neoplasm or psoriasiform spongiotic dermatitis can feel alarming even when the news is relatively straightforward. At Stratum Dx, we believe an informed patient (or referring provider) is a better-supported one. So let’s break down what’s actually going on when a pathologist reads your biopsy.
The Report Isn’t Always Black and White
When a dermatopathologist reviews a tissue sample, they’re doing detective work under a microscope. Sometimes the answer is clear: basal cell carcinoma, nodular type, present at margins. Clean, definitive, actionable.
Other times, the report reads more like a carefully worded maybe — and there’s a good reason for that.
What Is a Differential Diagnosis?
You may notice your report includes a “comment” section with something called a differential diagnosis. This is simply a ranked list of possibilities, with the most likely diagnosis at the top.
For example, a pathologist might identify tissue that looks like a nodular basal cell carcinoma — but certain features are missing (like clefting or myxoid stroma), or there’s additional differentiation present (like squamous or ductal features) that raises the possibility of a rarer tumor type, such as a hidradenocarcinoma. In that case, the pathologist is saying: this is almost certainly a carcinoma, but we want your physician to know the full picture.
A differential diagnosis isn’t a hedge — it’s precision.
Why Can’t They Always Be 100% Sure?
A few honest reasons:
Partial sampling. Your initial biopsy is usually not meant to remove the entire lesion — it’s meant to get enough tissue for a diagnosis so your doctor can plan the best next step. When only part of a tumor is sampled, the pathologist can’t always assess deeper features like infiltrative growth, perineural invasion, or tumor necrosis that would help confirm or rule out malignancy.
Prior treatment. If you’ve been using topical steroids, or are on systemic steroids for another condition, the inflammatory picture under the microscope can be altered. Steroids are powerful — they can suppress the very cells a pathologist is looking for. This is particularly relevant when ruling out conditions like mycosis fungoides (a type of skin lymphoma), where lymphocytes along specific skin layers are key diagnostic markers. Steroid use in the weeks prior to biopsy can reduce those cells significantly, making the sample harder to read.
Mixed features. Some skin conditions look a lot like each other. Psoriasiform spongiotic dermatitis is one example — a descriptive diagnosis that essentially tells your provider the tissue has features of more than one type of rash. It’s not a failure of the lab; it’s the honest truth of what the sample shows.
What Should You Do With This Information?
First: don’t panic over terminology. A complex-sounding report doesn’t automatically mean a complex or serious diagnosis.
Second: ask questions. Your dermatologist should be able to translate the pathology report into plain language and explain what the next steps are — whether that’s watchful waiting, re-biopsy, excision, or referral.
Third: be upfront about any treatments you’ve recently used, including over-the-counter steroids. That context matters to both your provider and the pathologist interpreting your sample.
The Bottom Line
Pathology is a collaboration. The pathologist gives your dermatologist the most accurate picture possible from the tissue available. Your dermatologist uses that picture — along with everything they know about you — to make the best clinical decision. And you, armed with a little more understanding of the process, are a full participant in that conversation.
Questions about a recent biopsy or skin concern? The team at Stratum Dx is here to help.