From the Latin adnexa meaning attached or conjoined, adnexal refers to the appendages of organs, in this case, of the skin. The large heterogenous group of malignancies arising from these appendages can represent both diagnostic and surgical management difficulties.
Clinically, these tumors are rather nondescript, presenting as enlarging dermal tumors. Some malignant adnexal tumors grow within their benign counterparts so a common presentation is recent growth in a long-standing tumor.
Surgery is the mainstay of treatment. Due to an infiltrative growth pattern, these tumors often extend more widely than is appreciated clinically so surgical plans can radically change intraoperatively. Most arise on the head and neck where tissue preservation is frequently a key concern.
Successful margin control surgery (MCS) is dependent on an accurate biopsy diagnosis and the ability to identify and track the tumor with frozen section examination. It is helpful to prepare the patient and the staff for the possibility of multiple levels, a long day, and a sizeable defect. A multistage procedure is often planned with a delayed reconstruction. The usual workflow is outlined in Table 13.1.
TABLE 13.1Usual Workflow ||Download (.pdf) TABLE 13.1 Usual Workflow
(i) Biopsy review, IHC, and diagnosis. Possible discussion in the multidisciplinary meeting (MDM)
(ii) Central debulk sent for paraffin assessment
(iii) MCS (paraffin or frozen section) to ensure clear margins. Be prepared for multiple levels, complex mapping, and chasing perineural invasion
(iv) Paraffin safety margin should be considered for difficult FS cases
(v) Consider delayed reconstruction after safety margin assessment
Given the rarity of some of these tumors, review of the biopsy is generally advisable. If the biopsy is not available for review, an onsite biopsy is recommended. The biopsy needs to demonstrate the way in which the tumor interacts with surrounding tissues, so a deep incisional biopsy is generally preferred. Correlating the histologic diagnosis with the clinical findings can be critical. For example, plaque-type syringoma is generally obvious clinically, but it may be misdiagnosed pathologically as microcystic adnexal carcinoma (MAC); MCS in this context (the unnecessary complete excision of a large benign syringoma) can have disastrous cosmetic and functional consequences.
The central tumor is debulked and sent for formal histology to confirm the diagnosis and check for risk factors (e.g., perineural invasion) which may not be evident on the initial biopsy. This tissue may also be used for further studies (diagnostic, therapeutic, or research).
Often the lesion is large, so a meticulous surgical diagram of serial blocking is important. The following figures demonstrate a typical difficult case (Figs. 13.1 to 13.4).
The clinical tumor is debulked and sent to the ...