PG Corner- Case 12

Dr Anuj ParkashWritten by | HISTOPATHOLOGY, PG CORNER

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Background

A 56-year-old female presented with postmenopausal bleeding. MRI pelvis showed bulky uterus with large myometrial fibroid having cystic degeneration. Total abdominal hysterectomy was done. Sections from the myometrial mass.

Microscopy

Fig.12a; H&E; 5x

Fig.12b; H&E; 10x

Fig.12c; H&E; 10x

Fig.12d; H&E; 20x

Fig.12e; H&E; 10x

Fig.12f; H&E; 10x

Images show areas of high-grade spindle cell sarcoma in fascicles and sheets [Fig.12a] with focal areas of myogenic differentiation [Fig.12b]. Many multinucleated tumor cells are seen [Fig.12c] along with sheets of epithelioid cells in myxoid background [Fig.12d]. Areas of heterologous differentiation in the form of osteosarcoma [Fig.12e] and chondroid differentiation [Fig.12f] are also noted.

No epithelial component is readily identified.


Fig.12g; CK

Fig.12h; SMA

Fig.12i; Desmin

On Immunohistochemistry, tumor cells are diffusely negative for CK [Fig.12g]. Areas with myogenic differentiation show positivity for SMA [Fig.12h] and Desmin [Fig.12i].


Final Impression: High Grade Leiomyosarcoma With Heterologus (Osteosarcoma/Chondrosarcoma) Differentiation.

 


  • Uterine leiomyosarcoma is a malignant mesenchymal tumor derived from smooth muscle cells
  • Age of presentation: 4th-5th decade of life
  • Location: Uterine corpus (common), cervix
  • Germline mutation in Fumarate Hydratase⇒ increased risk of developing uterine leiomyosarcoma
  • Genetic alteration: Frequently mutated genes:
    • TP53
    • ATRX
    • MED12
  • Subtypes:
Spindle cell leiomyosarcoma
Epithelioid leiomyosarcoma
Myxoid leiomyosarcoma
  • Spindle cells in long, interlacing fascicles

  • Multinucleated tumor cells

  • Osteoclast like cells
  • Round or polygonal cells with eosinophilic or clear cytoplasm

  • In nested, nodular or diffuse pattern
  • Paucicellular with abundant myxoid stroma

  • Nodular or vague fascicular growth pattern
  • Essential diagnostic criteria:
Spindle cell leiomyosarcoma
(Two or more of the following)
Epithelioid leiomyosarcoma
(One or more of the following)
Myxoid leiomyosarcoma
(One or more of the following)
  • Marked cytologic atypia

  • Tumor cell necrosis

  • ≥ 4mitosis/mm2  (equating to ≥ 10 mitosis/10 HPF of 0.55mm in diameter)
  • Moderate to severe atypia

  • Tumor cell necrosis

  • ≥ 1.6 mitosis/mm2 (equating to ≥ 4 mitosis/10 HPF of 0.55mm in diameter)
  • Any degree of atypia

  • Tumor cell necrosis

  • ≥ 0.4 mitosis/mm2 (equating to ≥ 1 mitosis/10 HPF of 0.55mm in diameter)

  • Infiltrative border
  • Rare cases with osseous and chondro-osseous differentiation have been reported in literature
  • Immunohistochemistry (Positive stains):
    • Desmin, h-caldesmon, SMA, CD10
    • EMA, CK (epithelioid leiomyosarcoma)
    • ER, PR, p16, p53 overexpression (Spindle cell leiomyosarcoma)
  • Differential diagnosis:
    • Smooth muscle tumor of uncertain malignant potential (Criteria):
      • Tumor cell necrosis: absent, focal moderate atypia, ≥5 mitosis/10HPF or,
      • Tumor cell necrosis: absent, diffuse severe to moderate atypia, 5-9 mitosis/10HPF or,
      • Tumor cell necrosis: present, none to mild atypia, <10 mitosis/10HPF
    • Atypical leiomyoma (Criteria):
      • Tumor cell necrosis- Absent
      • Focal moderate to severe atypia
      • <5mitosis/10HPF
    • Mitotically active leiomyoma (Criteria):
      • Tumor cell necrosis- Absent
      • None to mild atypia
      • ≥5mitosis/10HPF
    • Undifferentiated endometrial sarcoma:
      • Endometrium and myometrium location
      • Negative for Desmin, caldesmon and Actin
    • Rhabdomyosarcoma:
      • Rare in uterus
      • Search for rhabdomyoblast.
      • Positive for Desmin and Myogenin
      • Negative for caldesmon
  • Prognosis:
    • Aggressive, even with tumor confined to uterus
    • Recurrence (50-70%) occur in lung and in pelvis
    • Progression depends on stage
    • Size of neoplasm < 5cm (in Stage I tumor) and premenopausal women have more favourable outcome as seen in some studies
  • Treatment:
    • Postmenopausal women: Early-stage: TAH and BSO
    • Removal of ovary and lymph node is controversial, as metastasis to these organs occur in small percentage of cases
    • Premenopausal women: therapy is controversial
    • In stage I and II cases, role of adjuvant systemic therapy or radiotherapy on survival is uncertain
    • Some patients respond to hormonal therapy

Contributed by: Dr Sunil Pasricha

Compiled by: Dr Diksha Karki


In case of queries, email us at: kumar.ankur@rgcirc.org

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Last modified: 28/06/2021

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