Page 31 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 2-4 Benign Growths

Eccrine poroma on
the scalp. Glistening
red papule or nodule.
Can be located at
any location

ECCRINE POROMA

Eccrine poromas are the most common tumors in the Eccrine porocarcinoma. Nondescript
poroma family of skin tumors. Other tumors in this red papule or nodule. Ulceration may
family include the dermal ductal tumor, the poroid occur. A biopsy is required to diagnose
hidradenoma, and the hidroacanthoma. Eccrine poro- this rare form of skin cancer.
carcinoma is the rare malignant counterpart to the
eccrine poroma. Eccrine poromas develop from the
appendageal structures of the skin. The all-encompassing
term poroma is more accurate in that it appears that not
all of these tumors are derived from eccrine structures.
There is unconfirmed evidence that the cell of origin is
actually apocrine. Other possibilities for the cell of Low power. The tumor appears as an extension
origin include the sebaceous gland and the follicular of the epidermis. The finger-like projections
epithelium. of tumor cells extend into the dermis. There
Clinical Findings: Eccrine poromas are uncommon is a clear difference between keratinocytes
tumors of the skin. They occur equally in men and and the smaller tumor cells. Many blood
women and almost exclusively in the adult population. vessels are present within the tumor stroma.
They are typically small tumors, ranging from 5 to
20 mm. They are most frequently found on the soles
and palms. As many as 50% to 60% of these tumors
have been found on the sole, but they have been
described to occur in any skin location. Pain and bleed-
ing are the two most common symptoms encountered.
Eccrine poromas tend to have a vascular appearance
and often manifest as a red or purplish papule or nodule.
They are almost always solitary in nature, and they
easily bleed when traumatized. On inspection, the
eccrine poroma often has a slight, dell-like depression
surrounding the tumor. This is more commonly seen
on acral skin. This dell, when seen by the perceptive
clinician, often leads to a differential diagnosis that High power. A better appreciation
includes an eccrine poroma. There is nothing clinically of the stromal blood vessels is seen.
that can be used with certainty to make the diagnosis. The tumor cells are uniform in size
The differential diagnosis includes vascular tumors, and shape.
metastatic lesions (particularly the vascular renal cell
carcinoma metastasis), pyogenic granuloma, and mela-
noma, because some eccrine poromas exhibit pigmenta-
tion. The diagnosis is made by histological examination
after biopsy.
Histology: Eccrine poromas show varying degrees of
ductal differentiation. The tumor is well circumscribed
and has characteristic features. The keratinocytes have
been described as cuboidal. They tend to be small and
have an increased nuclear to cytoplasmic volume.
Necrosis is often seen in parts of the tumor. The ductal
portions of the tumor are lined by an eosinophilic layer The eccrine porocarcinoma is very uncommon; histo- require removal from a functional standpoint. Surgical
or cuticle. The stromal portions of the tumor are rich logically, it is a tumor that is poorly circumscribed and excision with a small (1-2 mm), conservative margin is
in vascular components. This vascular element imparts often found in conjunction with an eccrine poroma. Cells curative. The recurrence rate is very low after surgical
the red appearance to the tumor. Eccrine poromas can with multiple large nuclei and multiple mitoses help excision. Electrodesiccation and curettage has been
be histologically classified as other members of the make the diagnosis. Eccrine porocarcinomas can mimic used successfully. Eccrine porocarcinomas require sur-
poroma family of tumors, based on their location in the metastatic adenocarcinomas, and immunohistochemical gical excision and close clinical follow-up. Chemother-
skin. As an example, the hidroacanthoma, a member of staining is required to make certain of the diagnosis. apy is reserved for cases of metastatic disease. The role
this family, is defined as an eccrine poroma that is Treatment: Although they are benign tumors, eccrine of sentinel lymph node sampling in these tumors has
entirely located in the epidermis. poromas often are located on the sole or palm and yet to be defined.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 17