Palisaded Myofibroblastoma



Palisaded Myofibroblastoma


L. Jeffrey Medeiros, MD










A fixed excisional lymph node biopsy specimen shows replacement by palisaded myofibroblastoma. Note the central gray-white areas and subcapsular hemorrhage (“milk freshly poured into tea”).






Amianthoid fibers were prominent in this case of palisaded myofibroblastoma. Amianthoid fibers are composed of eosinophilic mats of degenerated collagen fibers with a starburst quality in this field.


TERMINOLOGY


Abbreviations



  • Palisaded myofibroblastoma (PM)


Synonyms



  • Intranodal palisaded myofibroblastoma


  • Intranodal hemorrhagic spindle cell tumor with amianthoid fibers


  • Myofibroblastoma


Definitions



  • Benign tumor of probable myofibroblastic origin that almost always arises in inguinal lymph nodes



    • Minority view suggests smooth muscle origin (from vessels or capsule)


ETIOLOGY/PATHOGENESIS


Acquired Abnormality



  • Inguinal lymph nodes have increased numbers of myofibroblasts compared with other lymph nodes


  • May be related to increased lymphatic drainage at this site



    • Predisposes to benign proliferation of myofibroblastic cells


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare tumor; approximately 50 cases reported in literature


  • Age



    • Wide age range: 19-71 years



      • Median: 6th decade


  • Gender



    • Slight male predominance (M:F = 4:1)


  • Ethnicity



    • No ethnic preference reported


Presentation



  • Painful mass


  • Unilateral; no side preference


  • Unicentric; rare multicentric cases reported


  • Almost all cases arise in inguinal lymph nodes



    • Located deeply; under inguinal ligament


    • Overlying skin is not involved


  • Rare cases reported in submandibular or cervical lymph nodes


Treatment



  • Surgical approaches



    • Excision is curative


    • No additional therapy required


Prognosis



  • Excellent



    • Benign lesion


    • Only 2 cases have recurred locally and needed reexcision



      • Recurrence at 6 years and 9 years


MACROSCOPIC FEATURES


General Features



  • Size: Range 0.6-5.0 cm in greatest dimension


  • Well encapsulated


  • Cut surface is gray-white and nodular with subcapsular hemorrhage



    • Likened to “milk freshly poured into tea”


MICROSCOPIC PATHOLOGY


Histologic Features

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Palisaded Myofibroblastoma

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