RDD can be differentiated from Erdheim-Chester diseaseand Langerhans cell histiocytosis on the basis of lesion alhistiocytes expressing both CD68 and S-100 protein while negative for
CD1a.8 Treatment depends upon the individual patient and is planned after determining the extent of the disease although no ideal treatment is available for all patients.
Moreover, immunohistochemistry showed reactivity for CD99 while the blasts were negative for plasma cell marker, CD138, Langerhans cell marker,
CD1a, cytotoxic T cell marker, perforin, pan-B marker, and pax5.
Histology reveals histiocytes and emperipolesis with immunohistochemistry positivity for S100 and CD68 but negative results for
CD1a. (41) Erdheim-Chester disease is a systemic histiocytosis affecting older patients and most commonly presents with bone pain.
Immunohistochemical and hematoxylin-eosin staining [Figure 1]e, [Figure 1]f, [Figure 1]g, [Figure 1]h, [Figure 1]i, [Figure 1]j, [Figure 1]k, [Figure 1]l, produced the following results as follows:
CD1a (+); S-100 (+, polyclonal); Kp-1 (+); phosphoglucomutase-1 (+); and Ki-67 (+ <25%).
Immunohistochemistry revealed neoplastic cells that were positive for S100 (Figure 2c),
CD1a (Figure 2d), CD68, CD14, and lysozyme.
Definitive diagnosis can be achieved only with the detection of
CD1a and S-100 proteins and Birbeck granules adhering to the cytoplasmic membrane.
In dendritic cells, the surface expression of antigen-presenting molecules (
CD1a, major histocompatibility complex class II, and costimulatory molecules CD40, CD80, and CD86) diminishes in the presence of calcitriol and does not fully mature.
It was supported by the detection of
CD1a and S-100 protein.
DC in MDS express lower levels of
CD1a, CD54, CD80, and MHC II molecules [26].
Eventually, the ulcer was biopsied, revealing a typical LCH pathology, with dermal infiltrate of morphologically characteristic Langerhans cells extending into the epidermis, which were positive for S100,
CD1a, and CD207, with other inflammatory cells (Figure 2).
Silva et al., "Langerhans cells (
CD1a and CD207), dermal dendrocytes (FXIIIa) and plasmacytoid dendritic cells (CD123) in skin lesions of leprosy patients," Microbial Pathogenesis, vol.
