Squamous neoplasia of the vulva is a common pathologic occurrence. It is now appreciated that squamous intraepithelial neoplasia can be subclassified into HPV-associated and HPV-independent forms, which differ with respect to etiology, age at diagnosis, natural history, and morphology. In North America, most preinvasive lesions are associated with HPV [1]. Localized primary cutaneous amyloidosis of the vulva, on the other hand, is uncommon in Europe and North America and is infrequently reported in the English language literature [2]. Localized cutaneous amyloidosis (LCA) of the vulva has been described in association with a spectrum of malignant and benign lesions, including VINs, lichen sclerosus, seborrheic keratosis, and benign vulvar skin [2] in a single case series in which 26 cases had localized amyloidosis and 1 case had systemic vulvar amyloidosis. Spherule-like amyloid deposition has not been previously reported in the vulva, nor in association with vulvar intraepithelial neoplasm (VIN).

The patient was a 59-year-old female, G2P1 (one prior vaginal delivery) with a history of VIN2 diagnosed on a prior vulvar biopsy. Her medical history was also remarkable for breast cancer status post right lumpectomy and lymph node biopsy 10 years ago. She was treated with radiation therapy, Tamoxifen for one year, and Anastrozole for five years, which was completed four years ago. In 2011 and 2012, she had a thickened endometrium on imaging, which prompted endometrial and endocervical sampling with features suggestive of endometrial and endocervical polyps in 2011. In 2014, multiple small-scattered condylomata were noted on physical examination. Human papillomavirus testing at that time was negative. In September 2018, she had a biopsy that was read as VIN2.

A vulvectomy was performed on October 2018 for management of the patient’s high-grade squamous intraepithelial neoplasia. The vulva was submitted in three specimens. The skin had an irregular surface with multiple tan-colored, raised, fleshy plaques ranging from 0.6 to 1.1 cm in largest dimension. The specimen was entirely submitted.

Microscopic evaluation of the specimens revealed high-grade squamous intraepithelial neoplasia (VIN2 and VIN3) with spherule-like deposition of amyloid (Figure 1D), (Figure 2A), and (Figure 2B). The amyloid deposition consisted of spherules resembling corpora amylacea. The amyloid exhibited a band-like dermal distribution (including the papillary dermis) (Figure 1A). A special stain for Congo red confirmed that the deposition is amyloid (Figure 1B) and (Figure 1C). Immunostain of amyloid P (AP) and immunohistochemical stain for pan-cytokeratin (PANCK) was positive while the immunostain for amyloid AA was negative. Immunohistochemical stains with adequate controls demonstrated the dysplastic epithelium to have block-like positivity for p16 and Ki-67 was increased, supporting the diagnosis of HPV-associated VIN and high-grade squamous intraepithelial lesion.

The association between HPV infection and amyloid deposition has been previously studied. It is known that abundant E4 protein assembles into amyloid fibrils that disrupt keratin structure and compromise the normal assembly of the cornified envelope [3]. It has been postulated that E4 amyloid fibers may contribute to virion release and infectivity in the upper layers of the epithelium [3]. It is known that E4 self-association allows the protein to form structures resembling amyloid fibers, which is critical in the pathogenesis of HPV [4]. Researchers have even performed structural analysis which revealed an amyloid form of the HPV type 16 E1×E4 protein and provided a molecular basis for its accumulation [5] (N-terminal deletion results in the assembly of the 16E1×E4 protein into ordered amyloidlike fibrils). These findings represent a growing body of literature that is bridging the gap between localized amyloid deposition and HPV infection.

Localized cutaneous amyloidosis is a condition characterized by the deposition of amyloid or amyloidlike proteins in the dermis. Amyloid is defined as in vivo deposited material characterized by an amorphous eosinophilic appearance on hematoxylin and eosin staining. It is classified chemically. All types of amyloid consist of one major fibrillary protein that defines the type of amyloid. Amyloidosis is referred by AL in which the fibril protein is an immunoglobulin light chain or light chain fragment. In AA amyloid, the “A” protein is a normalsequence apo-SAA (serum amyloid A protein), which is an acute phase reactant produced mainly in the liver in response to certain cytokines [6]. The AP component is a nonfibrillar normal plasma protein that is common to all forms of amyloid. Regardless of the protein precursor of amyloid fibrils in the different potential clinical scenarios, all amyloid deposits always contain abundant serum AP. Serum amyloid P binds avidly but reversibly to all types of amyloid fibrils and is thus specifically concentrated in all amyloid deposits [7],[8].

Amyloid spherules are a rare finding but have also been previously described. Notably, spherical amyloid is identified in the squash smear preparation of a patient with a pituitary prolactinoma [9]. Spherical amyloid aggregates have also been found to be neurotoxic, and may play a role in the neurodegeneration in Alzheimer’s disease [10]. However, to the best of our knowledge, it has not been described involving or in association with HPV-related lesions.

Localized cutaneous amyloidosis encompasses several conditions characterized by amyloid deposition, including but not limited to localized primary cutaneous amyloidosis of the vulva [11]. Primary cutaneous amyloidosis of the vulva is an entity that is very poorly described and understood in the English language literature. The only study that attempted to characterize the association between amyloid deposits in localized vulvar amyloidosis and their association with VIN concluded that the amyloid deposition appears to be associated with both high- and low-grade VINs. Like our case, these cases of amyloid deposition exhibited Congo red positivity. Our case also demonstrated block-like positivity for p16. Ki-67 was increased, supporting the diagnosis of HPVassociated VIN and high-grade squamous intraepithelial lesion. The immunostain for AP was positive while the immunostain for amyloid AA was negative. It is unclear (and unstudied) as to whether or not amyloid deposition is a causative factor in the development of high-grade VIN or is a consequence of the VIN, or if it plays a role in its pathogenesis. This rare and poorly studied association merits further research in order to provide additional insight on the nature of both LCA and high grade VIN.

In conclusion, spherule-like amyloid deposition has not been previously described in the vulva. However, localized amyloid deposition in the vulva has been seen in association with various benign and malignant lesions, including intraepithelial neoplasias. The full clinical significance of this finding is not certain at this time. We postulate that the presence of high-grade intraepithelial neoplasia is a causative factor in the formation of these amyloid deposits. Further research to elucidate the pathophysiology of these findings would be helpful in preventing the formation of these deposits and associated complications.