Pigmented epithelioid melanocytoma - A case report

Pigmented epithelioid melanocytoma

International Archives of Integrated Medicine, Vol.

Copy right © 2014, IAIM, All Rights Reserved.

Case Report


Tariq AL

Pathology consultant, King Khalid university hospital

*Corresponding author’s email:

How to cite this article: Tariq AL

A case report. IAIM, 2014; 1(3): 36

Available online at

Received on: 27-10-2014

Abstract

Pigmented epithelioid melanocytoma (PEM) is a

melanoma which is rare. It affects all age groups. The prognosis is relatively good compared to

conventional malignant melanoma.

with an asymptomatic brown-black lesion

had a diameter of 0.6 cm, appeared round, exophyt

edges and bluish reflections. All features strongly suggested nodular melanoma

excised and histopathology showed asymmetrical growth of heavily pigmented atypical epithelioid

and spindle cells. A pigmented epithelioid melanocytoma, so

diagnosed. The depth of invasion was classified as Clark level IV, with

Key words

Pigmented epithelioid melanocytoma, Animal

Introduction

Pigmented epithelioid melanocytoma (PEM) is

an unusual variant of malignant melanoma w

relatively indolent behavior. Dick

it and noted its predilection for gray horses and

named it as equine-type melanoma in 1832 [1].

In 1925, Darier delineated the parallelism

between these lesions and similar neoplastic

processes in humans, to which he gave the


International Archives of Integrated Medicine, Vol. 1, Issue. 3, November, 2014.

2014, IAIM, All Rights Reserved.


case report

Tariq AL-Johani*, Ahmed A. Alhumidi

King Khalid university hospital, P.O. Box 3844, Riyadh 11481

*Corresponding author’s email: [email protected]

Tariq AL-Johani, Ahmed A. Alhumidi. Pigmented epithelioid melanocytoma

36-38.

Available online at www.iaimjournal.com

2014 Accepted on:

Pigmented epithelioid melanocytoma (PEM) is a borderline melanocytic neoplasms or a low


conventional malignant melanoma. We presented here a case of 3 years old Saudi girl presented

black lesion on her left forearm. At clinical examination

a diameter of 0.6 cm, appeared round, exophytic, and intensely pigmented

ll features strongly suggested nodular melanoma

logy showed asymmetrical growth of heavily pigmented atypical epithelioid

and spindle cells. A pigmented epithelioid melanocytoma, so-called animal-type melanoma, was

diagnosed. The depth of invasion was classified as Clark level IV, with maximum thickness of 3 mm

Pigmented epithelioid melanocytoma, Animal-type melanoma, Malignant melanoma.

Pigmented epithelioid melanocytoma (PEM) is

malignant melanoma with

Dick first described

noted its predilection for gray horses and

type melanoma in 1832 [1].

In 1925, Darier delineated the parallelism

between these lesions and similar neoplastic

ns, to which he gave the

name melanotic sarcoma [2].

Zembowicz, et al. [3] proposed the term

pigmented epithelioid melanocytoma (PEM)

a group of lesions including cases previously

diagnosed as human animal

and epithelioid blue nevus [5].

described as epithelioid blue nevus in patients

with Carney complex. Current experience

indicates that PEM is best considered as a

borderline melanocytic neoplasms or a low

ISSN: 2394-0026 (P)

ISSN: 2394-0034 (O)

Page 36

Pigmented epithelioid melanocytoma - A

Riyadh 11481.

Pigmented epithelioid melanocytoma -

Accepted on: 30-10-2014

neoplasms or a low-grade


old Saudi girl presented

on her left forearm. At clinical examination, the lesion

ic, and intensely pigmented with well-defined

ll features strongly suggested nodular melanoma and the lesion was

logy showed asymmetrical growth of heavily pigmented atypical epithelioid

type melanoma, was

maximum thickness of 3 mm.

type melanoma, Malignant melanoma.

name melanotic sarcoma [2]. In 2004,

proposed the term

thelioid melanocytoma (PEM) for

a group of lesions including cases previously

diagnosed as human animal-type melanoma [4]

e nevus [5]. PEM was first

described as epithelioid blue nevus in patients

complex. Current experience

indicates that PEM is best considered as a

borderline melanocytic neoplasms or a low-




grade melanoma. PEM is extremely rare. It

affects all age groups. The prognosis is relatively

good compared to conventional malignant

melanoma.

Case report

A 3 years old Saudi girl presented with an

asymptomatic brown-black lesion on her left

forearm. The nodule had been observed since

birth and increasing in size in a few months.

There was no past history or family history of

malignant melanoma, blue nevus or Carney

complex. At clinical examination

a diameter of 0.6 cm, appeared round,

exophytic, and intensely pigmented

defined edges and bluish reflections. A

strongly suggested nodular melanoma

lesion was excised and histopatholo

asymmetrical growth of heavily pigmented

atypical epithelioid and spindle cells

Junctional nests and few single mela

epidermis were found. [Photo -

melanocytes showed pigmented melanocytes

indicating loos of maturation

Mitosis, necrosis, ulceration, and

infiltrate were absent. A pigmented epithelioid

melanocytoma, so-called animal

melanoma, was diagnosed. The depth of

invasion was classified as Clark level IV, with

maximum thickness of 3 mm.

Discussion

Zembowicz, et al. [3] recently proposed the term

PEM for a spectrum of melanocytic

previously diagnosed as human animal

melanoma [4] and epithelioid blue nevus [5].

This proposal was based on prospective analysis

and follow up of 41 cases of lesions of suspected

animal-type melanoma and their comparison to

11 examples of epithelioid blue nevus from the

original series of Dr Carney. Zembowicz




PEM is extremely rare. It

e groups. The prognosis is relatively

good compared to conventional malignant

old Saudi girl presented with an

black lesion on her left

forearm. The nodule had been observed since

size in a few months.

There was no past history or family history of

malignant melanoma, blue nevus or Carney

complex. At clinical examination, the lesion had

a diameter of 0.6 cm, appeared round,

ic, and intensely pigmented with well-

and bluish reflections. All features

strongly suggested nodular melanoma and the

topathology showed

asymmetrical growth of heavily pigmented

atypical epithelioid and spindle cells. [Photo - 1]

Junctional nests and few single melanocytes in

- 2] Deep dermal

melanocytes showed pigmented melanocytes

indicating loos of maturation. [Photo - 3]

Mitosis, necrosis, ulceration, and lymphocytic

absent. A pigmented epithelioid

lled animal-type

melanoma, was diagnosed. The depth of

invasion was classified as Clark level IV, with

, et al. [3] recently proposed the term

melanocytic tumors

previously diagnosed as human animal-type

melanoma [4] and epithelioid blue nevus [5].

This proposal was based on prospective analysis

and follow up of 41 cases of lesions of suspected

type melanoma and their comparison to

thelioid blue nevus from the

Carney. Zembowicz, et al. [3]

concluded that both groups of lesions were

either histologically indistinguishable or had

considerable histological overlap.

distinctive clinic-pathological variant o

melanocytic tumor of unknown malignant

potential. It is characterized by its unique

feature of indolent behavior compared to

conventional melanoma.

these lesions often have a wedge

configuration and are composed of heavily

pigmented dermal melanocytic tumor cells with

a mixture of epithelioid and spindled cells.

Mitosis can be seen, but is rare. The

histopathological differential diagnoses of PEM

include cellular blue nevus, malignant blue

nevus, Spitz nevus, deep penetrating n

epithelioid blue nevus. The

differentiating feature between PEM and

cellular blue nevus is the presence of abundant

epithelioid cells in PEM [6].

Photo – 1: Asymmetrical dermal growth of

heavily pigmented melanocytes

maturation. (H & E, 40 X)

Zembowicz, et al. [3] reported that the lymph

node metastasis was detected in 11 of the 24

cases (46%) in which lymph node sampling were

performed. Because PEMs are associated with

frequent sentinel lymph node metastas

should recommend sentinel lymph node

sampling in the management of these cases as a

ISSN: 2394-0026 (P)

ISSN: 2394-0034 (O)

Page 37

concluded that both groups of lesions were

either histologically indistinguishable or had

onsiderable histological overlap. PEM is a

pathological variant of

unknown malignant

potential. It is characterized by its unique

indolent behavior compared to

a. Histopathologically,

these lesions often have a wedge-shaped

configuration and are composed of heavily

mented dermal melanocytic tumor cells with

a mixture of epithelioid and spindled cells.

Mitosis can be seen, but is rare. The

histopathological differential diagnoses of PEM

include cellular blue nevus, malignant blue

Spitz nevus, deep penetrating nevus and

epithelioid blue nevus. The most specific

differentiating feature between PEM and

nevus is the presence of abundant

Asymmetrical dermal growth of

melanocytes without

reported that the lymph

node metastasis was detected in 11 of the 24

cases (46%) in which lymph node sampling were

performed. Because PEMs are associated with

ode metastases, we

should recommend sentinel lymph node

sampling in the management of these cases as a




diagnostic procedure. The current follow up is

still too short to make definitive statement

about the long-term prognosis in PEM, but the

experience thus far indicates that it has more

favorable prognosis than conventional

melanoma. However, PEM is not a benign tumor

as they can cause the patient’s death [

Photo – 2: High power Dermo-epidermal

junction showed some atypical junctional

melanocytes (indicated by arrows). (H & E, 400

X)

Photo – 3: Deep dermal melanocytes showed

pigmented melanocytes indicating loos of

maturation. (H & E, 400 X)




The current follow up is

still too short to make definitive statement

term prognosis in PEM, but the

es that it has more

favorable prognosis than conventional

melanoma. However, PEM is not a benign tumor

cause the patient’s death [4].

epidermal

junction showed some atypical junctional

ws). (H & E, 400

eep dermal melanocytes showed

pigmented melanocytes indicating loos of

References

1 Dick W. Melanosis in men and horses.

Lancet, 1832; 19: 192

2 Darier J. Le melanome malin

mesenchymateau ou

Bull Assoc Fr Cancer, 1925; 14: 221e49

3 Zembowicz A, Carney JA, Mihm MC.

Pigmented epithelioid melanocytoma, a

low grade melanoma indistinguishable

from animal type melanoma and

epithelioid blue nevus. Am J Surg Pathol,

2004; 28: 31.

4 Crowson AN, Magro CM, Mihm MC.

Malignant melanoma with prominent

pigment synthesis: ‘animal type’

melanoma - A clinical and histological

study of six cases with a consideration of

other melanocytic neoplasms with

prominent pigment synthesis. Hum

Pathol, 1999; 30: 543

5 Carney JA, Ferreiro JA. The epithelioid

blue nevus. A multi centric familial

tumor with important associations

including cardiac myxoma and

psammomatous melanotic

schwannoma. Am J Surg Pathol, 1996;

20: 259.

6 Zembowicz A, Mihm MC. Dermal

dendritic melanocytic proliferations: An

update. Histopathology, 2004; 45:

433e51.

Source of support: Nil

Conflict of interest: None declared.

ISSN: 2394-0026 (P)

ISSN: 2394-0034 (O)

Page 38

Dick W. Melanosis in men and horses.

Lancet, 1832; 19: 192.

Darier J. Le melanome malin

mesenchymateau ou melanosarcome.

Cancer, 1925; 14: 221e49.

Zembowicz A, Carney JA, Mihm MC.

Pigmented epithelioid melanocytoma, a

low grade melanoma indistinguishable

from animal type melanoma and

epithelioid blue nevus. Am J Surg Pathol,

AN, Magro CM, Mihm MC.

Malignant melanoma with prominent

pigment synthesis: ‘animal type’

A clinical and histological

study of six cases with a consideration of

other melanocytic neoplasms with

prominent pigment synthesis. Hum

543.

Carney JA, Ferreiro JA. The epithelioid

blue nevus. A multi centric familial

tumor with important associations,

including cardiac myxoma and

psammomatous melanotic

schwannoma. Am J Surg Pathol, 1996;

Zembowicz A, Mihm MC. Dermal

lanocytic proliferations: An

update. Histopathology, 2004; 45:

None declared.

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Pigmented epithelioid melanocytoma - A case report