Nodular Dermatitis, Histiocytes Predominant:

1. sarcoidal:
• interface, lichenoid:
1. lichen nitidus.
2. sarcoid.
• dermal, subcutaneous:
1. no evidence of foreign body:
• sarcoid.
• Crohn's disease.
• Melkersson-Rosenthal syndrome (cheilitis granulomatosa Miescher Melkerson Rosenthal).
2. evidence of foreign body:
   • silica granuloma.
   • tatto material (such as mercury, cobalt).
• peri-infundibular: granulomatous rosacea.
• pseudolymphoma with focal granuloma component HERE.
• perineural: tracking S100-positive nerve twigs [S08-16360 & CN08-48], suggests tuberculoid & dimorphous leprosy (but can't be "diagnosed" unless actually see organisms by stain), but sarcoid can also do it.
2. tuberculoid:
• no foreign body & infectious:
• no foreign body & noninfectious:
• foreign body:
3. palisaded:
• mucin:
• degenerated collagen early, coarse bundles late
• degenerated collagen, cholesterol clefts, lipophages
• ghost of venule in center & epithelioid histiocytes sometiomes in the periphery in a palisade (Churg-Strauss granuloma).
• fibrin: rheumatoid nodule.
• urate deposits: gout.
• vasculitis, fibrin, necrosis of inflammatory cells: papulonecrotic tuberculid.
• collagen bundles different from normal human ones: Zyderm (bovine) collagen reaction.
4. interstitial:
• mucin: granuloma annulare (GA).
• degenerated collagen plus mixed cell infiltrate: interstitial granulomatous dermatitis with arthritis.
5. suppurative:
   • no infectious agent identifiable:
   1. squames: ruptured millium, infundibular, or isthmic cyst.
   2. foreign material: metals, tattoo (mercury, cobalt), splinter, suture, cactus spine, silica, starch, drug injection, Talwin.
   • infectious agent identifiable:
     1. bacterial: botryomyces, blastomycosis-like pyoderma, rhinosclerom, cat scratch disease, lymphogranuloma venereum (LGV).
     2. mycobacterial: scrofuloderma, atypical mycobacterial infection, leprosy [S09-16360].
     3. actinomycotic:
     4. fungal, deep:
     5. fungal, other than deep:
     6. algal:
     7. protozoal:
     8. parasitic:

References:

1. 3/24/10 expert consult from Dr. David Scollard @ National Hansen's Disease Programs, Baton Rouge, LA.
2. leprosy testing write-up @ Specialty Labs, their file HERE as to any newest tests coming out.

(posted 29 December 2008; latest addition 2 February 2011)