Multifocal Pseudomyogenic Hemangioendothelioma Involving the Scalp and Nose, Misdiagnosed as A Sarcoma: A Rare Case Report
Neha MITTAL1,4, Bharat REKHI1,4, Priyamvada SINGHAL2, Munita BAL1,4, Swapnil RANE1,4, Asawari PATIL1,4, Shivakumar THIAGARAJAN3,4
1Department of Surgical Pathology, Tata Memorial Hospital, MUMBAI, INDIA
2Subharti Medical College, UTTAR PRADESH, INDIA
3Department of Head and Neck Surgical Oncology, Tata Memorial Hospital, MUMBAI, INDIA
4Homi Bhabha National Institute University, MUMBAI, INDIA
Keywords: Hemangioendothelioma, Soft tissue neoplasms, Epithelioid cells, Scalp, Sarcoma
This case report aims to present clinicopathological features of an extremely rare case of multifocal pseudomyogenic hemangioendothelioma
(PMHE) in the scalp.
A 21-year-old male developed multiple, focally ulcerated, nodules over the root of his nose and scalp. One of the skin lesions was sampled at
another dermatology clinic, where this was diagnosed as a sarcoma. A review of biopsy sections showed well-circumscribed dermal lesions,
comprising plump spindle and epithelioid cells, mimicking rhabdomyoblasts. Immunohistochemically, tumor cells were positive for AE1/AE3,
CD31, FLI-1 and ERG. INI-1 was retained. A diagnosis of PMHE was offered. Subsequently, the patient underwent wide excision and has been
asymptomatic for 8 months, post-surgery.
PMHE is rarely reported in the head and neck region, where it can constitute a diagnostic pitfall. Awareness of this tumor and appropriate
immunohistochemical stains are necessary for its timely diagnosis, in order to avoid radical treatments. A review of similar, previously
documented cases is presented.
Pseudomyogenic haemangioendothelioma (PMHE), previously
termed as epithelioid sarcoma-like hemangioendothelioma,
is currently defined as an intermediate
malignant, rarely metastasizing neoplasm, displaying vascular/
endothelial differentiation. It mostly occurs in the
soft tissues of lower extremities of young adult males. Histopathologically,
PMHE simulates high-grade sarcomas,
such as spindle cell rhabdomyosarcoma and epithelioid
. It has rarely been described in the bones 4,5
. The head and neck region constitutes one of the rarest
A 21-year-old male presented to a dermatologist with
multiple nodular lesions involving the skin of his scalp,
forehead, and root of the nose of 4 months duration. He
underwent a biopsy from the lesion over his nose which,
at two different laboratories, was reported as high-grade
sarcoma and leiomyosarcoma, respectively.
Thereafter, he was referred to us. During clinical evaluation,
he seemed to be in good general health. During local examination, there were multiple, painless, nodular, fleshy
lesions involving the skin of his scalp, forehead, and nose
(Figure 1A). A clinical diagnosis of cutaneous sarcoma was
considered. He underwent radiological evaluation and the
slides and paraffin blocks of his nasal lesion were reviewed.
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|Figure 1: A) Clinical
fleshy, cutaneous lesions,
including a few ulcerated,
involving the scalp and
the root of the nose.
B) Positron emission
(PET) scan showing
nodular cutaneous lesions
involving the nasal root
(arrow), and frontal and
left parietal region.
C) PET-CT scan
displaying an isointense
lesion involving the skin
and subcutaneous tissues
on the root of the nose
(arrow), sparing the
Positron emission tomography (PET) scan showed multiple
FDG-avid lesions involving the nasal root, and the frontal
and left parietal region, the largest measuring 12 mm x 7.9
mm (SUVmax = 7.02) (Figure 1B, C). A wide local excision
of the lesions, followed by a reconstruction with a free flap
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|Figure 2: Microscopic features. A) A cellular
spindle cell tumor, involving the dermis with
cells arranged in interlacing fascicles (H&E,
x100). B) Tumor composed of plump spindleshaped
cells with vesicular nuclei and abundant
eosinophilic cytoplasm, reminiscent of a myoid
appearance with few interspersed neutrophils
(H&E, x200). Inset: Higher magnification
showing cells with an abundant eosinophilic
cytoplasm and vesicular nuclear chromatin
During review, the tumor sections were tested for various
immunohistochemical antibody markers on an automated
Ventana Benchmark XT® platform.
The resection specimens of the root of the nose and
posterior scalp lesions were well-oriented, measuring 9 cm
x 4.5 cm x 0.5cm and 8.5 cm x 5.5 cm x 0. 6 cm, respectively.
Cut surfaces of both the specimens showed multiple greywhite,
focally ulcerating, fleshy lesions.
Microscopically, the biopsy revealed an infiltrating tumor,
composed of spindle-shaped cells, involving the dermis
and subcutaneous tissue.
Microscopic examination of the resection specimens
revealed infiltrative, focally well-demarcated lesions,
appearing as granulomas in lower magnification. The
tumor cells were arranged in interlacing fascicles (Figure
2A). On higher magnification, tumor cells were seen
insinuating in between the adnexal structures and dermal
nerves. Individual tumor cells were plump, spindle-shaped,
containing moderate to abundant eosinophilic cytoplasm;
central to eccentrically placed vesicular nuclei and
discernible nucleoli, reminiscent of a “myoid” appearance.
There were few bi- and multi-nucleate forms. Focal areas
displayed “rhabdoid-like” cells, containing eccentrically
placed crescentic nuclei and paranuclear eosinophilic
inclusions. Additionally, there were pseudo-microcysts
comprising cells with intracytoplasmic vacuoles. There
were no significant mitotic figures and/or necrosis (Figure
Immunohistochemically, tumor cells showed positivity
for AE1/AE3, FLI-1, CD31 and ERG, and negativity for
smooth muscle actin (SMA), desmin, CD 34, P40, CD1a,
S100 P and CD163. INI1/SMARCB1 was diffusely retained
(Figure 3A-D) (Figure 4). Ki67/Mib1 highlighted 8-10%
tumor cell nuclei in the highest proliferating areas. All the
resection margins and base of both the resection specimens
were free of tumor.
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|Figure 3: Immunohistochemical results. A) Tumor cells displaying diffusely positivity for AE1/AE3. (AE1/AE3 antibody, x100).
B) Tumor cells showing CD31 positivity (CD31 antibody, x400). C) Diffuse FLI-1 positivity (FLI-1 antibody, x400). D) Tumor cells
showing retained INI1 immunostaining (INI1 antibody, x200)
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|Figure 4: Tumor cells displaying diffuse ERG positivity (ERG
antibody, x 200).
Multifocal pseudomyogenic hemangioendothelioma
(PMHE) is characterized by young age, male predisposition,
extremity location, multifocality and dermal location.
Microscopically, it displays infiltrative borders and tumor
cells resembling rhabdomyoblasts 3
. Till date, only 12
cases of PMHE have been reported in the head and neck
region, including 2 cases in the scalp, as noted in the
present case 2-3,5-9
. Other reported uncommon sites
include mucosal involvement in a single case and lymph
node metastasis in 2 cases, of the head and neck region
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|Table I: Summary of clinicopathological parameters of cases of PMHE, reported in the head and neck region.
Lack of overt vascular differentiation and a close
resemblance, both clinically, as well as histologically, to other
relatively commoner sarcomas, along with unawareness of
this entity might mislead an unwary pathologist, as noted in
the present case, which was misdiagnosed at two different
In view of its overlapping features with other sarcomas,
certain immunohistochemical antibody markers,
including cytokeratins and vascular markers, along with
INI1/SMARCB1 are essential for its diagnosis 3. A
range of differential diagnoses have been considered in
earlier reported cases, including an epithelioid sarcoma,
rhabdomyosarcoma, epithelioid hemangioendothelioma, and sarcoma, not otherwise specified (NOS). The closest
differential diagnosis in the present case was an epithelioid
sarcoma, in view of a relatively superficial location,
younger age and immunohistochemical expression of
cytokeratin 6,8. However, a predominantly spindle
cell morphology, along with immunopositivity for CD31
and retained expression of INI1, ruled out this possibility
3,7-8. Positivity for epithelial antibody markers and
negative staining for skeletal muscle-specific markers,
namely desmin, myogenin and MyoD1, ruled out a spindle
cell rhabdomyosarcoma. It is noteworthy that most of
the differential diagnoses of a PMHE are high-grade and
relatively aggressive tumors.
Apart from its distinct morphological features and
immunohistochemical profile, PMHE is characterized by a
distinct molecular signature, in the form of a genetic fusion
between FOSB (19q) with a strong promoter, SERPINE
(7q22), ACTB(7p22), and recently WWTR1(3q25), all
of which lead to an upregulation of FOSB expression
9-11. This led to development of FOSB immunostain
for the diagnosis of PMHE 9. At the same time, FOSB
is also expressed in epithelioid haemangiomas and in
osteoblastomas. In view of unavailability, we could
not test our case with FOSB. Nonetheless, unequivocal
histopathological features supplemented with necessary
immunohistochemical markers were supportive of a
diagnosis of PMHE (Table II).
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|Table II: Results of immunohistochemical (IHC) markers tested in various cases of PMHE of the head and neck region, as reported
in the literature.
Contrary to some of its worrisome histopathological
features, PMHE has an indolent clinical course with
potential for local recurrence and a minimal risk of distant metastasis. Disseminated disease and metastasis has been
reported in 6% of the cases 9. Development of metastasis
after 5 years of the initial diagnosis, as previously reported,
implies the need for a prolonged follow-up in such cases
3. The treatment is mainly aimed at wide excision of the
lesions, instead of radical resections and adjuvant therapies,
which are considered for its mimics such as an epithelioid
sarcoma, malignant rhabdoid tumor and a spindle cell
rhabdomyosarcoma. Adjuvant local radiotherapy has been
offered in unresectable cases of PMHE. The present case
was treated with wide-excision. The patient is alive with no
evidence of disease, 8 months post-surgery.
In conclusion, PMHE is an uncommon, locally aggressive
tumor of abstruse vascular origin, and an uncertain
malignant potential affecting dermal and or subcutaneous
tissue of various anatomical sites in young males. The head
and neck, especially nose and scalp constitute its rare sites.
With only 12 such reported cases in world literature, the
present case, including its clinical impact, seemed worth
reporting. Awareness of this entity, careful assessment of
morphological features and certain immunohistochemical
markers are necessary for its correct and timely diagnosis,
in order to obviate unnecessary radical treatments, the
latter reserved for recurrences or unresectable tumors,
which in itself are exceedingly rare in these tumors.
CONFLICT of INTEREST
The authors declare no conflict of interest.
Concept: NM, BR, Design: BR, NM, Data collection
or processing: NM, BR, PS, MB, SR, AP, ST, Analysis
or Interpretation: BR, NM, Literature search: NM, BR,
Writing: NM, BR, PS, Approval: BR, NM, PS, MB, SR, AP,
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