Abstract

Introduction:

Neurocristic Cutaneous Hamartoma (NCH) is derived from aberrant development of the neuromesenchyme.  NCH of the scalp is uncommon and malignant transformation of the tumor is extremely rare. NCH commonly appears as pigmented skin and superficial soft tissue lesion and it can be congenital or acquired. We are reporting a case of malignant metastatic NCH.

Case Presentation:

A 56-year-old female presented with pink 1-2 cm scalp mass.  Biopsy showed a well-circumscribed dermal lesion composed of atypical pleomorphic epithelioid and spindle cells with scant cytoplasm and rare mitotic figures. SOX10 immunostain highlights the spindle cells. S100 highlights both spindle cell and epithelioid cell population. MITF highlights epithelioid cells but is mostly negative in spindle cells.  Dual Ki-67/ MART-1 stain reveals an increased cell proliferative index.  The tumor cells were negative for p63, AE1/ AE3, CK5/6, CD34, EMA, SMA. Desmin and CD10. A diagnosis of combined spindle cell proliferation with melanocytic and nerve sheath differentiation, consistent with neurocristic proliferation was rendered.  In the resection specimen with sentinel lymph nodes, one lymph node was positive for the 2.4 mm-metastatic tumor deposit.

Conclusion:

Discolored scalp lesion with irregular borders would include squamous cell carcinoma and melanoma in the differential diagnosis.  As shown in this case, NCH should be considered because it may mimic malignancy and can present with similar clinical symptoms. Careful histologic and immunohistochemical examination are important for correct diagnosis and proper treatment approach, including surveillance for the development of malignancy in the future.