Intercostal nerve plexiform neurofibroma

Case contributed by Dr Arkadi Tadevosyan

Presentation

Right chest wall small growing, painless tumor since childhood. Clinical history is otherwise clear.

Patient Data

Age: 25 years
Gender: Female

A well-circumscribed large soft tissue mass in the right anteroposterior chest wall.

  • with a widening of 4-5 intercostal space, smooth-edged remodeling of adjacent costal margins
  • displacing pectoral and serratus muscles anteriorly
  • protruding in its smaller part to the thoracic cavity, without features of pleural invasion

It demonstrates heterogeneous postcontrast enhancement, with areas of necrosis and some prominent vascularization. 

Lungs are clear, with no pleural or pericardial effusion. No lymphadenopathy. No other abnormalities are identified in whole-body scan (not shown). 

Findings are most consistent with tumor arising from the intercostal nerve with benign features.

Pathology

Gross examination shows a well-circumscribed lesion composed of spindle-shaped cells with wavy nuclei. A few mast cells and mucin were present.

Immunohistochemical staining was positive for S-100 protein and negative for CD34. 

SMA [clone: asm-1] - negative reaction in tumor cells, cytoplasmic expression in internal control.
CD34 [clone: QBEnd/10] - positive reaction only in vascular endothelium.
S100 [clone: poly] - intense cytoplasmic expression in all tumor cells.
Desmin [clone: DE- R-11] - negative reaction in tumor cells.
EMA [clone: GP1.4] - a cytoplasmic expression of moderate-intensity in all tumor cells.
MyoD-1 [clone: 5.8A] - negative.
Vimentin [clone: V9] - a cytoplasmic expression of moderate-intensity in all tumor cells and internal control.
CD117 [clone: EP10] - negative.
Synaptophysin [clone: 27G12] - negative.
AE1/3 [clone: AE1/3 20:1] - a cytoplasmic expression of moderate-intensity in all tumor cells.
CDK-4 [clone: D9G3E] - negative.

The diagnosis made was myxoid neurofibroma.

Case Discussion

Plexiform neurofibroma considered pathognomonic for neurofibromatosis type 1, therefore patient sent to undergo genetic testing.

Diagnostic criteria  - The hallmarks of NF1 are the multiple café-au-lait spots (CALS) and associated cutaneous neurofibromas. The diagnostic criteria developed by the NIH Consensus Conference in 1987 and updated in 1997 are based upon specific clinical features of NF1. According to these criteria, at least two of the following clinical features must be present to make the diagnosis of NF1:

  • Six or more café-au-lait macules >5 mm in diameter in prepubertal and >15 mm in diameter in postpubertal individuals; for each lesion, the longest diameter is measured.
  • Two or more neurofibromas of any type or one plexiform neurofibroma.
  • Freckling in the axillary or inguinal regions.
  • Optic glioma.
  • Two or more Lisch nodules (iris hamartomas).
  • A distinctive bony lesion such as sphenoid dysplasia or thinning of the long bone cortex with or without pseudoarthrosis.
  • A first-degree relative (parent, sibling, or offspring) with NF1 based upon the above criteria.

 

Special thanks to Dr. David Mamunts, "Davidyants Laboratories" Yerevan, Armenia for contributing histopathology report.

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Case information

rID: 71260
Published: 5th Oct 2019
Last edited: 7th Oct 2019
System: Chest, Oncology
Inclusion in quiz mode: Included
Institution: "AMC" Yerevan

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