Alveolar soft part sarcoma

From Libre Pathology
Jump to: navigation, search
Alveolar soft part sarcoma
Diagnosis in short

ASPS. H&E stain.

LM large cells (~30-50 μm) with abundant eosinophilic cytoplasm and an eccentric nucleus +/-nucleolus, arranged in nests/separated by thin septa - vaguely resembles alveoli (at low power)
LM DDx paraganglioma, clear cell renal cell carcinoma, alveolar rhabdomyosarcoma
Stains PAS +ve (cytoplasm)
IHC TFE3 +ve (suggestive of translocation)
EM intracytoplasmic crystal lattice with ~5 nm fibres spaced 10 nm apart
Molecular t(X;17)
Site soft tissue - usu. head and neck

Clinical history usu. slow growing mass
Prevalence rare
Prognosis ultimately poor

Alveolar soft part sarcoma, abbreviated ASPS, is a rare malignant soft tissue lesion typically seen in younger individuals.

General

  • Adolescents/young adults.
  • Children -- classically location: orbit and base of tongue.[1]
  • Typical indolent initially - ultimately a poor prognosis.[2]

Microscopic

Features:[3]

  • Arranged in nests/separated by thin septa; vaguely resembles alveoli (at low power).
  • Large cells (~30-50 μm) with abundant eosinophilic cytoplasm.
    • May be focally cleared.
  • An eccentric nucleus.
  • +/-Nucleolus, prominent.
  • +/-Multi-nucleation (common).

DDx:

Images

www:

Stains

  • PAS +ve (cytoplasmic) - considered the most useful.[4]
  • PASD +ve (cytoplasmic).

IHC

  • TFE3 +ve -- suggestive of characteristic translocation.
  • Desmin ~ 50% of cases.[2]

Others:[2]

  • EMA -ve.
  • Cytokeratins -ve.
  • HMB45 -ve.
  • Melan‐A -ve.
  • Chromogranin A -ve.
  • Synaptophysin -ve.

Molecular

  • t(X;17)(p11.2;q25).[5]

Note:

EM

  • Distinctive membrane-bound intracytoplasmic crystal lattice with ~5 nm fibres spaced 10 nm apart.[2]

Image:

See also

References

  1. Anbarasi, K.; Sathasivasubramanian, S.; Kuruvilla, S.. "Alveolar soft-part sarcoma of tongue.". Indian J Pathol Microbiol 54 (3): 581-3. doi:10.4103/0377-4929.85099. PMID 21934227.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Folpe, AL.; Deyrup, AT. (Nov 2006). "Alveolar soft-part sarcoma: a review and update.". J Clin Pathol 59 (11): 1127-32. doi:10.1136/jcp.2005.031120. PMC 1860509. PMID 17071801. //www.ncbi.nlm.nih.gov/pmc/articles/PMC1860509/.
  3. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 627. ISBN 978-0781765275.
  4. Zarrin-Khameh, N.; Kaye, KS. (Mar 2007). "Alveolar soft part sarcoma.". Arch Pathol Lab Med 131 (3): 488-91. doi:10.1043/1543-2165(2007)131[488:ASPS]2.0.CO;2. PMID 17516754.
  5. Online 'Mendelian Inheritance in Man' (OMIM) 606243