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ANSWER
The correct answer is fungal infection (choice “a”). If this condition had been fungal, it would have responded to one or more of the medications used to treat it. In this case, treatment failure demanded consideration of alternate diagnostic possibilities.
Lichen simplex chronicus (choice “b”), also known as neurodermatitis, was a good possibility, since it is the consequence of chronic rubbing or scratching in response to the itching caused by, for example, eczema.
Psoriasis (choice “c”) usually has adherent white scale on its surface, unless it’s in an intertriginous (skin on skin) area where scale gets rubbed off by friction.
The patient’s actual diagnosis, however, turned out to be Paget’s disease (choice “d”). See the Discussion for relevant details.
DISCUSSION
Biopsy showed changes consistent with a type of skin cancer called extramammary Paget’s disease (EMPD), an intradermal adenocarcinoma that tends to develop in areas where apocrine glands are found (eg, the anogenital and axillary areas).
The majority of EMPD cases represent adenocarcinoma in situ with extension from adnexal structures. Intraepidermal metastasis from noncutaneous adenocarcinomas (via local or lymphatic routes) accounts for a significant minority of cases (< 25%). Urogenital and colorectal carcinomas are the most common.
EMPD is more common in women and is rare before age 40. In addition to the usual intertriginous areas, other sites in which it may be found include eyelids and ears. The lesions typically itch but rarely hurt; they do, however, inevitably grow larger and more extensive.
The histologic changes of EMPD are identical to those seen in mammary Paget’s disease, though the latter virtually always involves the areola and nipple. It also signals the presence of an underlying intraductal breast cancer.
The main teaching point to be gleaned from this case is the concept of “cancer presenting as a rash,” of which there are several examples: cutaneous T-cell lymphoma, B-cell lymphoma, metastatic breast cancer, superficial basal cell carcinoma, and intraepidermal squamous cell carcinoma (Bowen’s disease).
EMPD is especially prone to being overlooked, not only because groin rashes are so common but also because most skin cancers are “lesional” (ie, they take the form of a papule or nodule). Any rash that proves to be unresponsive to ordinary treatment should be either referred to dermatology or biopsied.
TREATMENT
This patient was prescribed imiquimod 5% cream, to be applied three times a week, which has a good chance of clearing the condition (but only after three to four months of application). If this fails, the patient will be referred for Mohs surgery.
Even so, recurrences are common. About 25% of EMPD patients with underlying malignancies eventually die of their disease. For these reasons, the patient was referred back to his primary care provider for workup for a possible underlying malignancy.
ANSWER
The correct answer is fungal infection (choice “a”). If this condition had been fungal, it would have responded to one or more of the medications used to treat it. In this case, treatment failure demanded consideration of alternate diagnostic possibilities.
Lichen simplex chronicus (choice “b”), also known as neurodermatitis, was a good possibility, since it is the consequence of chronic rubbing or scratching in response to the itching caused by, for example, eczema.
Psoriasis (choice “c”) usually has adherent white scale on its surface, unless it’s in an intertriginous (skin on skin) area where scale gets rubbed off by friction.
The patient’s actual diagnosis, however, turned out to be Paget’s disease (choice “d”). See the Discussion for relevant details.
DISCUSSION
Biopsy showed changes consistent with a type of skin cancer called extramammary Paget’s disease (EMPD), an intradermal adenocarcinoma that tends to develop in areas where apocrine glands are found (eg, the anogenital and axillary areas).
The majority of EMPD cases represent adenocarcinoma in situ with extension from adnexal structures. Intraepidermal metastasis from noncutaneous adenocarcinomas (via local or lymphatic routes) accounts for a significant minority of cases (< 25%). Urogenital and colorectal carcinomas are the most common.
EMPD is more common in women and is rare before age 40. In addition to the usual intertriginous areas, other sites in which it may be found include eyelids and ears. The lesions typically itch but rarely hurt; they do, however, inevitably grow larger and more extensive.
The histologic changes of EMPD are identical to those seen in mammary Paget’s disease, though the latter virtually always involves the areola and nipple. It also signals the presence of an underlying intraductal breast cancer.
The main teaching point to be gleaned from this case is the concept of “cancer presenting as a rash,” of which there are several examples: cutaneous T-cell lymphoma, B-cell lymphoma, metastatic breast cancer, superficial basal cell carcinoma, and intraepidermal squamous cell carcinoma (Bowen’s disease).
EMPD is especially prone to being overlooked, not only because groin rashes are so common but also because most skin cancers are “lesional” (ie, they take the form of a papule or nodule). Any rash that proves to be unresponsive to ordinary treatment should be either referred to dermatology or biopsied.
TREATMENT
This patient was prescribed imiquimod 5% cream, to be applied three times a week, which has a good chance of clearing the condition (but only after three to four months of application). If this fails, the patient will be referred for Mohs surgery.
Even so, recurrences are common. About 25% of EMPD patients with underlying malignancies eventually die of their disease. For these reasons, the patient was referred back to his primary care provider for workup for a possible underlying malignancy.
ANSWER
The correct answer is fungal infection (choice “a”). If this condition had been fungal, it would have responded to one or more of the medications used to treat it. In this case, treatment failure demanded consideration of alternate diagnostic possibilities.
Lichen simplex chronicus (choice “b”), also known as neurodermatitis, was a good possibility, since it is the consequence of chronic rubbing or scratching in response to the itching caused by, for example, eczema.
Psoriasis (choice “c”) usually has adherent white scale on its surface, unless it’s in an intertriginous (skin on skin) area where scale gets rubbed off by friction.
The patient’s actual diagnosis, however, turned out to be Paget’s disease (choice “d”). See the Discussion for relevant details.
DISCUSSION
Biopsy showed changes consistent with a type of skin cancer called extramammary Paget’s disease (EMPD), an intradermal adenocarcinoma that tends to develop in areas where apocrine glands are found (eg, the anogenital and axillary areas).
The majority of EMPD cases represent adenocarcinoma in situ with extension from adnexal structures. Intraepidermal metastasis from noncutaneous adenocarcinomas (via local or lymphatic routes) accounts for a significant minority of cases (< 25%). Urogenital and colorectal carcinomas are the most common.
EMPD is more common in women and is rare before age 40. In addition to the usual intertriginous areas, other sites in which it may be found include eyelids and ears. The lesions typically itch but rarely hurt; they do, however, inevitably grow larger and more extensive.
The histologic changes of EMPD are identical to those seen in mammary Paget’s disease, though the latter virtually always involves the areola and nipple. It also signals the presence of an underlying intraductal breast cancer.
The main teaching point to be gleaned from this case is the concept of “cancer presenting as a rash,” of which there are several examples: cutaneous T-cell lymphoma, B-cell lymphoma, metastatic breast cancer, superficial basal cell carcinoma, and intraepidermal squamous cell carcinoma (Bowen’s disease).
EMPD is especially prone to being overlooked, not only because groin rashes are so common but also because most skin cancers are “lesional” (ie, they take the form of a papule or nodule). Any rash that proves to be unresponsive to ordinary treatment should be either referred to dermatology or biopsied.
TREATMENT
This patient was prescribed imiquimod 5% cream, to be applied three times a week, which has a good chance of clearing the condition (but only after three to four months of application). If this fails, the patient will be referred for Mohs surgery.
Even so, recurrences are common. About 25% of EMPD patients with underlying malignancies eventually die of their disease. For these reasons, the patient was referred back to his primary care provider for workup for a possible underlying malignancy.
A 60-year-old man is referred to dermatology for evaluation of a somewhat itchy, unilateral groin rash. For several years, it has waxed and waned, never completely resolving. Recently, the rash has grown in size, and the itching has intensified, causing the patient to lose sleep. The patient has tried several OTC and prescription topical medications for this problem: creams containing clotrimazole, tolnaftate, 1% hydrocortisone, and betamethasone/clotrimazole, as well as triple-antibiotic ointment and several different moisturizing creams and lotions. He also tried a two-week course of oral terbinafine (250 mg/d). Additional questioning reveals a history of atopy, eczema, and asthma as a child. There is a strong family history of similar problems. This strikingly red, blistery-appearing rash is palm-sized and confined to the right groin. It has a fairly well–defined, scaly border that is KOH-negative on microscopic examination. Within the borders of this lesion are several focal, shiny, somewhat atrophic areas in which no epidermal adnexae (pores, follicles, hair, skin lines) can be seen.
