Papillary hidradenoma

A papillary hidradenoma, also termed hidradenoma papilliferum or mammary-like gland adenoma of the vulva,

Typically, papillary hidradenomas are solitary, slow-growing, small tumors that may have been present for months to many years before the time of diagnosis.[8] The tumors are usually symptomless but may be intermittently or constantly painful, become ulcerated, and exhibit minor levels of bleeding.^[9] The pain resulting from these tumors may be simple tenderness, more or less constant usually mild pain,^[4][9] or, in females, dyspareunia, i.e. pain during and just after sexual intercourse.^[4]

Rarely, papillary hidradenomas have progressed to what appear to be 1) in situ malignancies (i.e. malignancies that have neither metastasized nor invaded beyond the layer of tissue where they arose); 2) locally invasive malignancies;

In a review of 264 women diagnosed with anogenital papillary hidradenomas, patients ranged in age from 25 to 82 years (median: 49 years); in 25 cases where the information was available, the tumors had been present for 2–120 months (median: 12 months) with 13 patients reporting their tumor's presence for less than 1 year before diagnosis. All patients had a solitary tumor in the anogenital area except for one patient who presented with four clustered tumors. Most tumors involved the vulva (71.6%) and areas around the anus (14%) or space between the anus and vulva, i.e. the perineum (3.8%). Their lesions ranged in size from 0.2 to 2 centimeters (cm.) in largest dimension (median: 0.7 cm.).^[8] Smaller studies on one or a few females with anogenital papillary hidradenomas found that the tumors commonly presented as asymptomatic, well-confined, skin-colored, red, or bluish nodules^[14] in women of Caucasian origin between the ages of 25–66 years.^[4] The nodules were solid or cystic;^[10] 0.4 to 2.5 cm. in widest dimension;^[9][10] and usually located in the grooves (termed interlabial sulci or interlabial folds) between the labia majora and labia minora,^[9] the clitoris, or the region between the vulva and anus (i.e. Frenulum of labia minora).^[4] Ectopic papillary hidradenomas in women have been reported to occur on the scalp, eyelid, cheek, forehead, face, ear canal, and back. Nearly 50% of ectopic papillary hidradenoma have been diagnosed in men; these have occurred on the thigh, arm, armpit, face and eyelid.^{[15][16][17][18][7]} While usually symptomless, patients may complain that the tumor is ulcerated, bleeds, or is painful.^[9] This pain may be simple tenderness, more or less constant but usually mild,^[4][9] or, in females with anogenital lesions, dyspareunia.^[4] The rare cases of ectopic papillary hidradenoma in the external auditory canal have presented with unilateral conductive hearing loss sometimes associated with ear pain, drainage of ear fluid, or weakness of a facial muscle(s).^[18]

Histopathology

Microscopic

• 
  Intermediate magnification
• 
  Very high magnification

Immunohistochemistry

The treatment of choice for anogenital and ectopic papillary hidradenomas, regardless of their locations, is similar: resection of the tumor while preserving the surrounding structures.[9]^[15][18] Recurrence of these tumors is rare and usually due to incomplete removal of the primary lesion. As of 2021, there has been no reported recurrence of ectopic papillary hidradenomas.^[7] Prognosis after complete surgical removal of anogenital and ectopic papillary hidradenomas is excellent.^[15]

Malignant transformation of papillary hidradenomas

Transformations of papillary hidradenomas into malignant forms are extremely rare. Two cases progressed to in situ (malignant cells present in the tumor but have neither metastasized, i.e. spread to distant tissues nor invaded beyond the layer of tissue from where they arose) cancers; two cases appeared to have infiltrated locally but not metastasized;^[11] and one case was a rapidly fatal lesion that appeared to be an adenosquamous carcinoma that arose in a papillary hidradenoma.^[24] It is not clear that these cases actually represent true progression of papillary hidradenoma into a cancer.^[11]

See also

• Hidroacanthoma simplex
• List of cutaneous conditions

References