Granuloma annulare

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Granuloma annulare
Diagnosis in short

Granuloma annulare. H&E stain.

LM Palisading granulomas around necrobiotic collagen and mucin
Subtypes superficial (common), deep (not common)
LM DDx rheumatoid nodule, necrobiosis lipoidica, epithelioid sarcoma
Stains alcian blue stain (pH 2.5)
Gross usu. arms and hands
Site skin


Granuloma annulare is relatively uncommon problem in dermatopathology.

General

  • Benign and self-limited condition.
  • Etiology unknown - may be assoc. with trauma.[1]

Gross

  • Typically extremities - usu. arms and hands.[1]

Image

Microscopic

Features:[2]

  • Dermal palisading granuloma - typically superficial-to-mid dermis - surrounds:
    • Necrotic collagen - key feature.
      • Nuclei "missing" - have undergone karyolysis.
    • Mucin - important.
      • Loose/pale, paucicellular, eosinophilic.
  • Chronic inflammatory cells.

Notes:

  1. There may be multiple small foci with intervening normal dermis.[1]
  2. Granuloma annulare can be subclassified into subcutaneous and interstitial.
  3. Histomorphologically similar to Rheumatoid nodule.
  4. Neutrophils may be seen.[3]

DDx:

  • Necrobiosis lipoidica - little mucin, no normal dermis between foci,[1] plasma cells - common,[4] may involve the fat - tend to be deeper.
  • Rheumatoid nodule - has fibrin in the core of the granuloma (instead of mucin), multinucleated macrophages more common.[5]
  • Epithelioid sarcoma - esp. if the lesion appears to be mid-to-deep dermis.

Images

www:

Stains

Image:

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Skin lesion, left elbow, excision:
- Palisading granulomas with cores of necrobiotic collagen, and scant mucin
  consistent with granuloma annulare.

COMMENT:
An alcian-blue stain (pH 2.5) shows scant mucin.  The granulomas are relatively deep;
however, plasma cells are not apparent. The differential diagnosis is rheumatoid nodule.

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 51. ISBN 978-0443066542.
  2. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 478. ISBN 978-0781765275.
  3. Requena, L.; Fernández-Figueras, MT. (Jun 2007). "Subcutaneous granuloma annulare.". Semin Cutan Med Surg 26 (2): 96-9. doi:10.1016/j.sder.2007.02.006. PMID 17544961.
  4. URL: http://dermnetnz.org/pathology/necrobiosis-lipoidica-path.html. Accessed on: 24 January 2012.
  5. Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 52-3. ISBN 978-0443066542.
  6. 6.0 6.1 Yun, JH.; Lee, JY.; Kim, MK.; Seo, YJ.; Kim, MH.; Cho, KH.; Kim, MB.; Lee, WS. et al. (May 2009). "Clinical and pathological features of generalized granuloma annulare with their correlation: a retrospective multicenter study in Korea.". Ann Dermatol 21 (2): 113-9. doi:10.5021/ad.2009.21.2.113. PMC 2861218. PMID 20523767. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861218/.