case_images: PMC5376917_01
case_images: Clinical presentation: close view picture of conjunctival bleeding with eyelid hemorrhage and periorbital edema (a); voluminous infiltrative and erythematous nodule localized on the scalp (b); detailed view of bruise-like brown cutaneous nodules and plaques (c); multiple bruise-like brown cutaneous nodules and plaques localized on the back (d).
case_images: CRIHEM2017-4984951.001.jpg
case_images: PMC5376917_01_CRIHEM2017-4984951.001.jpg
case_images: fig1
case_images: Physical exam showed conjunctival bleeding, brown nodular bruise-like lesions on the scalp, neck, and back (Figures 1(a), 1(b), 1(c), and 1(d)), and bilateral cervical and submandibular lymph nodes enlargement.
case_images: Biopsy of dorsal cutaneous nodule: EE20x dermal-hypodermal blast infiltration, disrupting collagen and muscle tissues, with nodular distribution, sparing epidermidis (a); EE 100x (b) and EE400x (c) dermal-hypodermal monomorphous infiltration by middle-sized blastic elements, with irregular nuclei, small nucleolus, and scant cytoplasm.
case_images: CRIHEM2017-4984951.002.jpg
case_images: PMC5376917_01_CRIHEM2017-4984951.002.jpg
case_images: fig2
case_images: Skin biopsy showed a diffuse dermal and hypodermal infiltration by immature cells, with irregular nuclei and scant cytoplasm, with a perivascular and periadnexal pattern, involving nervous structures (Figures 2(a), 2(b), and 2(c)).
case_images: Laterocervical lymph node biopsy: EE20x (a), EE100x (b), and EE400x (c) diffuse and partially nodular infiltration by blast cells with complete effacement of lymph node architecture.
case_images: CRIHEM2017-4984951.003.jpg
case_images: PMC5376917_01_CRIHEM2017-4984951.003.jpg
case_images: fig3
case_images: A lymph node biopsy proved complete architectural effacement secondary to massive infiltration by analogous cells with the following IHC expression: CD4+ CD10+ CD56+ CD99+ CD123+ CD303+ TdT+ BCL2+; CD68PGM1+/- CD7+/- CD43+/- CD2-/+; CD3- CD5- CD8- CD20- CD30- CD34- CD79a- CD117- CD138- MPO- TIA1- PAX5- CyclinD- (Figures 3 and 4).
case_images: Lymph node immunohistochemistry analysis: immunostaining for TdT showing partial positivity (a); CD4 positive immunostaining (b); CD10 immunostaining on cell surface (c); CD56 positive immunostaining (d).
case_images: CRIHEM2017-4984951.004.jpg
case_images: PMC5376917_01_CRIHEM2017-4984951.004.jpg
case_images: fig4
case_images: A lymph node biopsy proved complete architectural effacement secondary to massive infiltration by analogous cells with the following IHC expression: CD4+ CD10+ CD56+ CD99+ CD123+ CD303+ TdT+ BCL2+; CD68PGM1+/- CD7+/- CD43+/- CD2-/+; CD3- CD5- CD8- CD20- CD30- CD34- CD79a- CD117- CD138- MPO- TIA1- PAX5- CyclinD- (Figures 3 and 4).
case_images: Immunophenotype of the bone marrow showing a large blastic plasmacytoid dendritic cell population (green): the blasts were large-sided cells with variable side scatter properties (a) and were weakly positive for CD45 (b); positive for CD4 (c), CD56 (c, d, e), CD123 (d), CD10 (e), and HLADR (f); partly positive for CD2 (g); and negative for CD34 (e), CD117 (f), CD19 (h), CD22 (h), CD13 (i), CD14 (i), cytCD3 (j), and cytCD79a (j).
case_images: CRIHEM2017-4984951.005.jpg
case_images: PMC5376917_01_CRIHEM2017-4984951.005.jpg
case_images: fig5
case_images: CD4+ CD10+ CD38+ CD45RA+ CD56+ CD123+ HLADR+; CD2-/+ CD7-/+ TdT-/+; CD1a- CD3- CD5- CD8- CD11b- CD11c- CD13- CD14- CD15- CD16- CD19- CD20- CD22- CD25- CD33- CD34- CD36- CD64- CD66c- CD117- CD138- CD235a- cytCD3- cytCD22- cytCD41- cytCD61- cytCD79a- cytMPO- (Figure 5). Conventional cytogenetics on BM showed normal karyotype, and no BCL2 rearrangement was detected by hybridization and molecular analyses; heavy chain immunoglobulin gene and TCR gamma chain gene showed polyclonal rearrangement. Cerebrospinal fluid FCM displayed a cluster of CD4+ CD10+ CD56+ CD123+ blast cells, coherent with occult central nervous system localization.