Microcystic Adnexal Carcinoma: Know Its Causes and Treatment

Introduction:

Microcystic adnexal carcinoma is a rare disease. It is a malignant tumor of sweat glands that commonly occurs in the head and neck region, particularly in the center of the face. It may occur in the axilla, trunk, genitals, and extremities rarely. It is said to be the infiltrative tumor that appears as a scare-like blemish on the skin exposed to the sun. It rarely shows lymph node metastasis (spread of cancer cells from one part of the body to another). Microcystic adnexal carcinoma is an uncommon tumor. This tumor can invade bone, blood vessels, cartilage, muscles, and nerves. The metastatic potential of this carcinoma is less, but its recurrence rate is high. They also have a perineural invasion. Microcystic adnexal carcinoma occurs in older individuals. Both males and females are affected equally, but some research shows that females are more prone. It occasionally affects children.

What Are the Alternative Names for Microcystic Adnexal Carcinoma?

Microcystic adnexal carcinoma can be mentioned as

• Sclerosing sweat duct carcinoma (SSDC).

• Syringomatous carcinoma.

• Malignant syringoma.

• Syringoid eccrine carcinoma.

• Sweat gland carcinoma with syringomatous features.

The tumor named syringomatous adenoma is also considered microcystic adnexal carcinoma.

What Causes Microcystic Adnexal Carcinoma?

Microcystic adnexal carcinoma is caused by

• Immunosuppressive drugs.

• Ultraviolet radiation.

• Radiation therapy.

Ultraviolet radiation is considered the major cause as the lesions in microcystic adnexal carcinoma are found in sun-exposed skin areas, especially in specific skin types. Microcystic adnexal carcinoma is found more in young individuals frequently exposed to ultraviolet radiation, such as fighter pilots.

Microcystic adnexal carcinoma is also caused by immunosuppressive drugs, which is unclear; thus, it is said that immunosuppressive drugs cause basal cell carcinoma and squamous cell carcinoma. In addition, immunosuppressive drugs are used in people with autoimmune diseases such as rheumatoid arthritis, type 1 diabetes mellitus, Hashimoto's thyroiditis, etc.

How Does Microcystic Adnexal Carcinoma Look?

Microcystic adnexal carcinoma is a slow-growing tumor. It appears as a single white to pink plaque-like lesion on the face or trunk. It usually appears at the center of the face. Initially, the tumor may appear as an elevated lesion, and it gets a nodule appearance over time.

Microcystic adnexal carcinoma has a perineural spread so the patient may complain of numbness, pain, tingling, burning, and itching sensations.

Under a microscope, microcystic adnexal carcinoma appears similar to trichoadenoma, infiltrative basal cell carcinoma, and syringoma. However, the key feature distinguishing it from other tumors is that there will be a zone of differentiation between the epithelial cells and tumor cells.

What Are the Diagnostic Methods for Microcystic Adnexal Carcinoma?

• Usually, it is challenging to differentiate microcystic adnexal carcinoma clinically as other skin-colored growths are found on the head and neck region.

• An incisional biopsy can diagnose microcystic adnexal carcinoma. Punch biopsies and excisional biopsies can also diagnose them. However, the tumor primarily lies in the deep dermis, so that a superficial biopsy can lead to the wrong diagnosis.

• If microcystic adnexal carcinoma is diagnosed as the next step, the patient should undergo a skin examination of the full body.

• The patient should also undergo a lymph node examination to confirm metastasis.

• Fine needle aspiration or excisional biopsy should be done in the enlarged lymph nodes.

• CT or MRI may detect the perineural invasion.

• Sometimes dermoscopy may also help diagnose microcystic adnexal carcinoma.

What Are the Treatments for Microcystic Adnexal Carcinoma?

Microcystic adnexal carcinoma is surgically treated by small incision or Mohs microsurgery. The advantage of using Mohs micrographic surgery over simple incision is that the margins are determined in Mohs micrographic surgery. Thus, it reduces the visits for the procedures.

• Intraoperative frozen sections help guide the conventional incision during surgery when the Mohs micrographic surgery lacks procedure availability.

• Patients are advised to visit the doctor for follow-up every six to twelve months. The follow-up included the full body examination of skin and lymph node examination.

• The lymph nodes should be surgically excised in severe lymph node metastasis cases.

• Chemotherapy with carboplatin or paclitaxel is suggested if the patients refuse surgical management. They may remain tumor-free for six years after this therapy.

What Is the Differential Diagnosis of Microcystic Adnexal Carcinoma?

The differential diagnosis of microcystic adnexal carcinoma is

• Morpheaform basal cell carcinoma.

• Desmoplastic squamous cell carcinoma.

• Desmoplastic trichoepithelioma.

• Trichoadenoma.

• Syringoma.

The more significant plaque-like lesion of microcystic adnexal carcinoma is also a differential diagnosis.

What Are the Complications of Microcystic Adnexal Carcinoma?

If microcystic adnexal carcinoma is not treated, its lesion may invade the vital structures. This invasion of essential organs depends on the location of the lesion. In some cases, death may also occur if left untreated.

The post-surgical complications are also included. They may be

• Bleeding.

• Urinary retention.

• Blood clot.

• Post anesthetic effect.

• Wound infection.

What Are the Challenges Faced by Healthcare Providers in Microcystic Adnexal Carcinoma?

Doctors find it difficult to diagnose microcystic adnexal carcinoma due to the small pimple-like appearance of the lesion. These patients may present with small papule-like lesions on the head and neck for a longer time. However, clinical findings of the tumor make it challenging to diagnose the healthcare providers, and they may interpret this condition by biopsy. Dermatologists are well-versed in diagnosing microcystic adnexal carcinoma, but they also need help from some more specialists in finding the disease; they are Mohs surgeons, an otolaryngologist, and radiologists. Nurses play a vital role in this interprofessional group as they educate patients and their families. The pharmacist also plays a role as they are involved in ensuring patients' medicine and whether they are taking the correct antibiotics and analgesics.

What Is the Prognosis of Microcystic Adnexal Carcinoma?

Microcystic adnexal carcinoma has a poor prognosis as its recurrence rate is high. After surgery, microcystic adnexal carcinoma can occur within two to three years. However, in some cases, they may reoccur after a decade. Death may occur if the tumor invades the vital organs.

Conclusion:

Proper diagnosis and proper treatment will help the patients overcome the disease in a better way. Reaching out to specialized doctors is necessary. Though microcystic adnexal carcinoma is rare, it should be diagnosed soon when suspected.