PART TWO
Diagnostic Cytology
Fig. 18.16 Kaposi sarcoma. (A) Histologic section. Vascular proliferation presents as vessels and slit-like spaces containing red blood cells (H&E x MP). (B)
Smear. Overlapping spindle cells with fusiform to cigar-shaped nuclei with inconspicuous nucleoli and fine chromatin pattern (H&E x MP).
Key features of juvenile hemangioma
• Spindle cells arranged in compact 3-dimensional
clusters;
• Cells with scant to moderate amount of homogenous
cytoplasm;
• Nuclei with an even distribution of slightly coarse
chromatin; and
• No anaplasia, mitosis, or prominent nucleoli.
Lymphangioma
Lymphangiomas are benign cavernous vascular lesions composed
of dilated lymphatic channels most common in early childhood;
they have been associated with Turner syndrome. The most com-
mon sites of the cystic type are the neck, axilla, and groin, while
the cavernous types are most common in the mouth, upper
trunk, and limbs.83 Histologically, these lesions are characterized
by the presence of thin-walled, lymphatic vessels of different
sizes lined by flat endothelium and surrounded by lymphocytic
infiltrate. Cytologically, the FNA of these specimens yields red
blood cells and lymphocytes, with some histiocytes intermin-
gled. These cells are associated with a proteinaceous background.
A polymorphous lymphoid population is present.84,85
Key features of lymphangioma
• Proteinaceous background; and
• Red blood cells and polymorphous lymphoid popula-
tion, with some admixed histiocytes.
Kaposi Sarcoma
Kaposi sarcoma is a locally aggressive tumor associated with
human herpes virus 8 (HHV-8) infections.86,87 The four forms
of Kaposi sarcoma are classic indolent, endemic African, iatro-
genic, and acquired immunodeficiency syndrome-associated.
Clinically, it usually presents as purplish, reddish blue, and dark
brown patches, plaques, or nodules involving mainly the skin,
but solid organs can also be involved. Histologically, there is a
vascular proliferation, which is perivascular and periadnexal at
early stages. The vascular proliferation presents as vessels and
slit-like spaces containing red blood cells (Fig. 18.16A). The
endothelial cells have little atypia with mitotic figures seen in
the nodular stage. Hyaline globules are noted more frequently
in the plaque and nodular stage. An inflammatory infiltrate can
be seen associated with this vascular proliferation. Cytologi-
cally, Kaposi sarcoma is characterized by moderately cellular and
bloody specimens, overlapping spindle cells, and ill-defined
cytoplasmic borders (Fig. 18.16B). Nuclear crush artifact can be
present. Smaller groups of loosely cohesive spindle-shaped cells
and individual spindle cells with cytoplasm are also seen. The
cells might display cytoplasmic vacuoles, cytoplasmic hyaline
drops, and hemosiderin granules. The nuclei are fusiform to cigar-
shaped nuclei with inconspicuous nucleoli and fine chromatin
pattern. Red blood cells are frequently noted in between the
spindle cells.88-91 The differential diagnosis includes intranodal
myofibroblastoma, schwannoma, leiomyoma, melanoma, fibro-
sarcomas, and vascular transformation of lymph node sinuses.
The detection of HHV-8, which is possible on cytology material,
plays an important role as a confirmatory ancillary study.
Key features of Kaposi sarcoma
• Moderately cellular and bloody specimens;
• Overlapping spindle cells with ill-defined cytoplasmic
borders;
• Fusiform to cigar-shaped nuclei with inconspicuous
nucleoli and fine chromatin pattern;
• Spindle cells with possible cytoplasmic vacuoles, cyto-
plasmic hyaline drops, and hemosiderin granule; and
• Red blood cells frequently noted in between the
spindle cells.
Epithelioid Hemangioendothelioma
Epithelioid hemangioendothelioma is a vascular tumor with
metastatic potential. It is composed of cells with epithelioid
morphology and arranged in nests and cords embedded in
myxohyaline stroma. This tumor is rare and can occur at any
age and usually in the deep soft tissue of extremities. It is char-
acterized histologically by a vascular proliferation composed
of short nests and strands of round cells (Fig. 18.17A). These
484
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