Diagnostic Atlas of Cutaneous Mesenchymal Neoplasia E-Book

J. Eduardo Calonje, Alexander J Lazar, Bostjan Luzar

• Éditeur: Elsevier
• Année: 2019
• ISBN:
  9780323295819
• Sujet: Medicine
• Sous-sujet: Pathology

With its many diagnostic categories, relevant variants, and rare tumors, soft tissue pathology is one of the most challenging areas of surgical pathology. Focusing on the cutaneous soft tissue specimens and reactive mimics most likely to be encountered by pathologists and dermatopathologists, Diagnostic Atlas of Cutaneous Mesenchymal Neoplasia is a superbly illustrated, easy-to-use atlas designed to be used beside the microscope for efficient diagnosis and classification of soft tissue tumors of the skin.

• Features high-quality histologic and clinical images of multiple examples of each tumor, with captions and bulleted text for quick reference.
• Uses a high-yield format that facilitates a rapid and accurate diagnosis, including:
• • Characteristic clinical setting
  • Key morphologic features
  • Immunohistochemical properties
  • Molecular diagnostic testing (where applicable)
• Offers the most complete presentation available of this complex family of tumors, authored by renowned experts in dermatopathology.

1

Adipocytic tumors

• Benign tumors and reactive conditions
  • Lipoma
  • Lipomatosis
    • Multiple symmetric lipomatosis (Launois-Bensaude syndrome)
    • Asymmetric lipomatosis
  • Lipomatosis of nerve
  • Adiposis dolorosa
  • Piezogenic pedal papules
  • Fat necrosis of the morbidly obese
  • Nevus lipomatosus superficialis
  • Fibrohistiocytic lipoma
  • Lipofibromatosis
  • Lipoblastoma/lipoblastomatosis
  • Lipoblastoma-like tumor of the vulva
  • Angiolipoma
  • Myolipoma of soft tissue
  • Myelolipoma
  • Chondroid lipoma
  • Spindle cell lipoma
  • Pleomorphic lipoma
  • Hibernoma
• Malignant tumors
  • Atypical lipomatous tumor/well-differentiated liposarcoma/dedifferentiated liposarcoma
  • Spindle cell liposarcoma
  • Myxoid liposarcoma
  • Pleomorphic liposarcoma

Benign tumors and reactive conditions

Lipoma

Definition

• • A benign dermal or subcutaneous mesenchymal tumor composed of mature adult-type adipose tissue

Clinical features

Epidemiology

• • The most commonly encountered mesenchymal tumor
• • Majority of patients are adults
• • No sex predilection

Presentation

• • Most cases are asymptomatic
• • Occasionally painful when compressing nerves
• • Slowly growing, but size is variable
• • Usually solitary
• • Multiple lipomas may be associated with neurofibromatosis, multiple endocrine neoplasia syndromes, or Bannayan syndrome (hemangiomas and multiple lipomas)

Prognosis and treatment

• • Treated mostly for aesthetic reasons
• • Cured by conservative surgical excision
• • Recur only if incompletely excised and then only rarely
• • Not associated with progression to liposarcoma

Pathology

Histology

• • Resemble normal adult-type adipose tissue
• • Lobules of adipocytes bounded by thin fibrous septa
• • Adipocytes have large single lipid vacuole in their cytoplasm and eccentrically located small nuclei
• • May show areas of fat necrosis and increased fibrosis after trauma
• • No atypia, pleomorphism, mitoses, or hyperchromasia

Immunohistochemistry/special stains

• • Adipocytes express S100 protein

Genetic profile

• • True neoplasms
• • Translocation at 12q14 involving HMGA2 gene is the most common aberration, often with LPP (3q27)
• • 6p21-23 rearrangements involving HMG1B gene are also seen

Main differential diagnoses

• • Normal adipose tissue
• • Pseudolipomatosis cutis
• • Atypical lipomatous tumor

Fig. 1 Lipoma. Deeper lipomas are well-circumscribed neoplasms composed of mature adipose tissue essentially indistinguishable from normal fat.

Fig. 2 Lipoma. High-power view of mature adipocytes exhibiting minimal size variatio...