#dermpathJC January 2020:
Thursday, January 23rd, 9 pm EST
Article discussed: Invisible dermatosis, disgnostic discrepancy between the general pathologist and dermatopathologist
Authors: Ahmed Alhumidi, Najd Alshamlan, Mona Alfaraidi, Khaled Mohajer
Temporary open access courtesy of Journal of Cutaneous Pathology at: : https://onlinelibrary.wiley.com/doi/pdf/10.1111/cup.13554
Summary prepared by: Cacey Peters, M.D. (@caceypeters)
Journal Club Summary:
- Invisible dermatoses are those that have subtle histologic features but have been biopsied because of obvious clinical lesions.
- Often, a diagnosis of no significant pathological changes or nonspecific findings will be made by a general pathologist.
- 81 total cases were reviewed over the past 15 years where general pathologists, with experience ranging from 5-20 years, made one of the following diagnoses:
- No specific diagnosis
- No significant pathologic changes
- Minimal pathologic changes
- These cases were reviewed retrospectively and blindly by a dermatopathologist trained at a reputable center in the United States with 5 years of experience in dermatopathology.
- Out of 81 total cases, 43 (53%) were found to have a specific diagnosis while the remaining 38 (46.9%) remained non-specific. Of the nonspecific cases, 15 (39.47%) were due to inadequacy of the specimen.
- This study aims to highlight the diagnostic challenges of invisible dermatosis, the importance of clinicopathologic correlation, biopsy adequacy/preparation, and histochemistry.
- Conditions that are likely to receive a nonspecific diagnosis by a general pathologist include:
- Becker’s melanosis
- Clinically pigmented patches
- Shoulder, back, or chest
- Histologically – regular elongation of the rete ridges with basal hyperpigmentation
- Spongiotic dermatitis – intercellular epidermal edema
- Id reaction
- Pityriasis rosea
- Pityriasis alba (children, hypopigmented patches that can mimic mycosis fungoides)
- Many others
- Pigmented purpuric dermatosis (extravasated red blood cells and hemosiderin-laden macrophages)
- Progressive pigmentary dermatosis of Schamberg (subtle deposits and scant inflammation)
- Purpura annularis telangiectodes of Majocchi
- Eczematoid-like purpura of Doucas and Kapentanakis
- Pigmented purpuric dermatitis of Gougerot and Blum
- Increased dermal mucin (often subtle, can use Alcian blue and colloidal iron stains)
- Generalized myxedema
- Pretibial myxedema
- Lichen myxedematosus
- Papular mucinosis
- Reticular erythematous mucinosis
- Self-healing juvenile cutaneous mucinosis
- Pityriasis/tinea versicolor (caused by Malassezia furfur)
- Acute generalized exanthematous pustulosis (AGEP)
- Mycosis fungoides (cutaneous T-cell lymphoma)
- Urticaria (if resolves within 24 hours; if chronic, suspect urticarial vasculitis)
- Primary cutaneous amyloidosis (HMWCK+)
- Telangiectasia macularis eruptive perstans (TMEP; mastocytosis, highlighted by Giemsa, toluidine blue, and CD117)
- Becker’s melanosis
This pie chart illustrates the types of diagnoses were rendered by dermatopathologists when they reviewed pathology slides without significant pathology or no diagnosis report.
Differential diagnosis of invisible dermatoses. A mnemonic by @SGottesmanMD.
Thank you so much for attending #DermpathJC and for reading this summary.
We are always here for you and your dermatopathology learning,