Custom Search




A Systematic approach to diagnose Cutaneous Infections by Dermatopathologists

Dr Sampurna Roy MD       




1) Granulomatous  Pattern

2) Type of Inflammatory Cellular Infiltrate 

3) Changes in the epidermis

4) Changes in the Dermis and Cutaneous Appendages

5) Spindle cell Pseudotumour

6) Invisible dermatoses


1) Granulomatous  Pattern:  



- Tuberculoid granuloma: Lupus Vulgaris , Tuberculosis tuberculoid leprosysyphilis , cryptococcus .           


- Suppurative granuloma:


 Image of suppurative granuloma

Atypical Mycobacterial Infection , Lymphogranuloma venereum , Blastomycosis-like pyoderma  

- Palisading granuloma: Phaeohyphomycosis, Cryptococcosis , coccidioidomycosis, mycobacteriosis.   


- Histiocytic granuloma: Infection: Atypical mycobacteria , lepromatous  leprosy , malakoplakia ; leishmaniasis.     

 .1  2   3  4

1) Lepromatous leprosy - Hematoxylin and eosin stain. ; 2) Ziehl Neelsen staining showing the lepra bacilli. 3)Malakoplakia  4) Parasitized macrophages in Leishmaniasis


2) Type of inflammatory cellular infiltrate:            

- Prominence of plasma cells:  Syphilis

; ,

Chancroidlymphogranuloma venereum .

- Prominence of eosinophils: Arthropod bite, helminth infestation.

- Prominence of neutrophils:

Impetigo Granuloma Inguinaleerysipelas, erythema nodosum leprosum, blastomycosis-like pyoderma ,  chancroid , mycetoma , actinomycosis , phaeohyphomycosis , mucormycosis.  

- Presence of histiocytes and plasma cells:  

Rhinoscleroma , syphilis , granuloma inguinale.

- Presence of parasitized macrophages and parasitized multinucleated giant cells: 

  i) Presence of parasitized macrophages: Rhinoscleroma  


Lepromatous leprosy   ; toxoplasmosis , histoplasmosis, leishmaniasis .

  ii) Parasitized multinucleated giant cells: fungal infection.


3. Changes in the epidermis:  

- Psoriasiform epidermal hyperplasia: Chronic candidosis

- Pseudoepitheliomatous hyperplasia: Amoebiasis , toxoplasmosis  , blastomycosis-like pyoderma, tuberculosis , human papilloma virus infections , verrucous herpes/ varicella lesions in HIV infection.

- Epidermal spongiosis:   Dermatophytoses , candidosis , viral infection, cutaneous larva migrans , arthropod bites , cercarial dermatitis.

- Intraepidermal vesiculation:  Herpes Simplex Virus Infection , Herpes Zoster Virus , varicella. These are characterized by intranuclear inclusions and ballooning degeneration.


4. Changes in the Dermis and Cutaneous Appendages:     

- Superficial and deep dermal perivascular inflammatory infiltrate

 ;  ; Arthropod bite (eosinophils are noted) , leprosy , secondary syphilis (lymphoplasmacytic infiltrate).

- Folliculitis and perifolliculitis: , Dermatophytosis  , pityrosporum folliculitis,  syphilis, , demodex infestation, pyogenic bacterial infection.

- Vasculitis: Necrotizing fasciitis, erythema nodosum leprosum, meningococcal and gonococcal septicemia, rickettsial infections, cytomegalovirus infection, recurrent herpes.

- Tissue necrosis:  Cat Scratch Disease, ecthyma gangrenosum, Mycobacterium ulcerans Infection , necrotizing fasciitis, diphtheria.

5. Spindle cell pseudotumour:

Histioid Leprosy , atypical mycobacteria.

6. Invisible dermatoses:  

Section appears almost normal when stained with Hematoxylin and eosin stain Dermatophytosis, Pityriasis versicolor ;  Erythrasma.



Identification of fungi in tissue section:

- Periodic Acid Schiff with or without diastase is the most commonly used special stain. Cell wall stains purple with Periodic Acid Schiff.

Cryptococcus is stained with mucicarmine stain or a combined alcian blue- Periodic Acid Schiff stain. The cell wall and the capsule appear in contrasting colour.

- Silver methenamine stain (Grocott's method). Stains fungi  black against green backround.  It is more reliable than Periodic Acid Schiff for detecting degenerate fungal organisms.       

- Gomori methenamine silver with Hematoxylin and Eosin counterstain demonstrate fungi and tissue components simultaneously.

- Calcofluor white used to stain frozen or paraffin sections and viewed with a fluorescence  microscope.

- Autofluorescent fungi include Blastomyces, Cryptococcus, Candida , Aspergillus Coccidioidomycosis and sometimes Histoplasma.

- Polymerase chain reaction (PCR) technique :  Used to identify specific species of fungi.

Histochemistry in identification of microorganisms in skin sections:

- Pyodermas (impetigo and its variants and ecthyma) - Cocci demonstrated by Gram stain

- Erythrasma - small coccobacilli in stratum corneum- Gram stain, Periodic Acid Schiff and methenamine silver positive.

- Tuberculosis and non-tuberculous (atypical) mycobacterial.

Acid fast bacilli identified by Ziehl Neelsen stain. 

- Leprosy - Hematoxylin-eosin and Fite Faraco staining method on tissue section are sufficient for evaluation.

Sometimes Gomori - methenamine silver stain help to detect remnants of Mycobacterium Leprae in treated patients.

- Histioid Leprosy - Acid fast bacilli  arranged parallel to long axis of cell.


- Granuloma Inguinale and Chancroid - Gram negative bacilli - Demonstrated by Warthin Starry (silver) and Giemsa stain

- Rhinoscleroma - Periodic Acid Schiff, Gram and Warthin starry stains positive.

- Malakoplakia  - Periodic Acid Schiff positive diastase resistant inclusions. Calcospherites (Michaelis Gutmann bodies) are Von Kossa - positive.

- Rickettsia- Organisms demonstrated in endothelium or vessel wall using fluorescein-labelled antisera or with immunoperoxidase techniques.

- Spirochaete -Treponema pallidum and its subspecies are demonstrated by silver impregnation technique -  Levaditi or Warthin-Starry.

- Actinomycosis -  Granules are composed of slender filaments - Gram and Periodic Acid Schiff positive and stains grey or black with silver methenamine.

Not acid fast.

Club shaped bodies at the periphery and matrix of granules are Gram negative.

- Nocardiosis - Gram positive & weakly acid fast. Also stains with silver methenamine.

- Leishmaniasis -  Leishman-Donovan bodies are better identified in sections stained with Weigert iron hematoxylin than those stained with hematoxylin and eosin or the Giemsa stain.









Infectious Disease Online


Pathology Quiz Online 


Paediatric Pathology Online


Pancreatic Pathology Online




Endocrine Pathology Online


Eye Pathology Online


Ear Pathology Online


Cardiac Path Online


Pulmonary Pathology Online


Lung Tumour Online




Nutritional Pathology Online


Environmental Pathology Online


Soft Tissue Tumour Online


GI Path Online-India


Gallbladder Pathology Online


E-book - History of Medicine  


Microscope - Seeing the Unseen




Privacy Policy  

Advertising Policy

Copyright 2018