A scoping review on clinicopathological characteristics,diagnosis,and management of intermammary pilonidal sinus disease

Abstract

Background:

Intermammary pilonidal sinus disease (IMPSD) is a rare condition that primarily affects the young population. Due to the absence of standardized guidelines, IMPSD poses significant challenges during management.

Objectives:

This scoping review aims to map and characterize the existing literature on IMPSD to provide an overview of clinicopathological characteristics, risk factors, diagnosis, and management.

Eligibility Criteria:

Studies were included if they were original articles, case reports, or case series that met the inclusion criteria published in English during 2004 to 2024.

Sources of Evidence:

A search was conducted using MeSH keywords “Intermammary” AND “Pilonidal sinus” in PubMed, Google Scholar, and by citation searching up to date.

Charting Methods:

The PRISMA ScR guidelines were used as a charting method. Data extraction included demographic characteristics, clinical pathological characteristics, diagnostic methods, treatment approaches, and follow-up outcomes.

Results:

Ten articles met the inclusion criteria, including 33 patients with a mean age of 18.7 years. The majority of cases were reported from Turkey, Iraq, and India. Mean body mass index was 28.74 kg/m². Significant other comorbidities included polycystic ovary syndrome in 24% of cases. Large pendulous breasts and wearing tight brassieres were noted as other risk factors. Clinical presentation commonly involved discharging sinuses and painful swellings, with a mean duration of 8 months. Complementary investigations were seldom performed as the diagnosis was mainly clinical. The main modes of treatment included resection with primary closure or resection with secondary healing.

Conclusion:

Low prevalence and management challenges highlight the need for further research to establish standardized guidelines and the importance of formulating an individualized plan for the management of IMPSD based on a comprehensive evaluation of clinicopathological characteristics and patient wishes.

Introduction

Intermammary pilonidal sinus disease (IMPSD) is an inflammatory disorder caused by hair penetrating the epidermis. ¹ It is defined as a blind end tract bordered with granulation tissue that develops into a cystic cavity lined with epithelial tissue. ² Pilonidal sinus (PNS) is commonly present in the sacrococcygeal region, whereas, on rare occasions, it may manifest in the intermammary area. ³

PNS usually manifests in younger people between the ages of 10 and 40 years and those over 40 years have a reduced incidence. ⁴ This parallels the age distribution of IMPSD, which has a mean age of 20.4 years. ⁵

Risk factors associated with PNS include hirsute status, family history of PNS, wearing tight clothes, and body mass index (BMI). These factors demonstrate a statistically significant difference between patient and control groups. ⁶ Obesity, hyperhidrosis (excessive sweating), inadequate personal hygiene practices, a sedentary lifestyle, and repetitive trauma to the affected area have also been noted as risk factors in the literature. ⁷ The literature mentions that obese females with an increased distribution of hair and large pendulous breasts are at higher risk of developing IMPSD. ⁸ In addition, hyperpigmentation and the use of tight-fitting brassieres are considered significant risk factors. ³

When considering the pathophysiology of PNS, the exact pathogenic mechanism underlying PNS development is speculative. Two popular theories offer possible explanations: Initially, hair gets entrenched under the dermis in locations that are subjected to increased pressure and friction, especially in parts of the skin that are sensitive. Second, inward growth results from the blockage of hair follicles by the accumulation of germs and debris. According to a related notion, regular cutaneous strain and movement may stretch hair follicles, leading to a rupture and subsequent inward growth. ⁴

The diagnosis of PNS is usually based on clinical assessment, and complementary investigations are seldom needed for the diagnosis. ⁹ Individuals suffering from IMPSD disease may exhibit a wide range of clinical symptoms, from acute infections to chronic infections, and in certain instances, they are asymptomatic. Acute symptoms include discomfort, fever, intermittent discharge (bloody, purulent, or mucous), and systemic symptoms like malaise, especially in cases where abscesses are present. Patients with chronic conditions typically experience discharge along with repeated, continuous pain, which represents the chronic nature of the condition. ⁴

Regarding the management of IMPSD, a conservative approach is used for asymptomatic pits and incision and drainage for acute abscesses. Using minimally invasive techniques such as laying tracts open reduce recurrence and improve cosmesis. ¹⁰ In recurring diseases, wide excision with secondary intention healing reduces the chance of recurrence but requires a longer healing time, while excision with primary closure with sutures has a higher chance of recurrence but allows for a quicker recovery. The application of topical natural polyphenols and laser epilation are two emerging non-surgical methods. ²

IMPSD poses several challenges in management. This condition mainly affects young girls. ² Many of these patients suffer due to the unsightly scarring occurring in the intermammary region with repeated surgery. This challenging clinical course is made worse by the lack of well-established therapeutic guidelines due to the rarity of the disease.

Therefore, we have carried out a scoping review on IMPSD. This scoping review aims to map and characterize the existing literature on IMPSD. Through the consolidation of existing literature, our objective is to improve our understanding of IMPSD and identify efficacious treatment approaches. The ultimate goal of this endeavor is to enhance patient outcomes and the quality of life of those who are affected by this condition.

Methodology

Search strategy

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for scoping reviews guideline was used for the study design, search strategy, screening, and reporting. ¹¹ A systematic search was conducted using MeSH keywords as follows: “Intermammary” AND “Pilonidal sinus” in PubMed, the Google Scholar website, and by citation searching up to date. All the articles were written in English.

Study selection criteria

Studies were independently selected by two members of the research group. In case of disagreement, a discussion was held between the two and the third member until the matter was resolved. The following criteria were used to include studies in this scoping review: (1) Original articles, case reports, and case series including patients diagnosed with intermammary pilonidal sinus. (2) Articles should include clinical details relevant to intermammary pilonidal sinus, which include patient demographics, clinical presentation, diagnostic methods, treatment approach, and follow-up outcomes. (3) Articles published in the last 20 years (2004–2024). Studies were excluded if the data were insufficient to diagnose intermammary pilonidal sinus, animal studies, in vitro studies, and duplicate publications.

Accordingly, 11 articles were selected and analyzed. The literature search protocol is summarized in Figure 1.

Figure 1.

PRISMA ScR flow chart.

Data extraction

Two members of the group independently assessed the quality of each study and extracted data from the papers, and the results were compared. Any conflicts were discussed and resolved with a third investigator. The data extraction checklist included the name of the first author, period of data collection, year of publication, country the study was performed, type of study, number of patients in each intervention, mean age, clinical presentation, the type of management, evaluation frequency and mean follow-up time, clinical response and the complications (Table 1).

Table 1.

Characteristics of the studies.

Author	Type of study	Year of publication	Country
Mirande et al. 7	Case report (1)	2022	USA
Özkan et al. 12	Case series (9)	2022	Turkey
Patel et al. 2	Case report (1)	2020	India
Deshpande et al. 13	Case report (1)	2020	India
Akbulut and Dirican 14	Case report (2)	2020	India
Yiğit et al. 4	Case report (1)	2020	Turkey
Ferahman et al. 15	Case series (12)	2020	Turkey
Isik et al. 16	Case report (1)	2019	Turkey
Salih et al. 17	Case report (1)	2018	Iraq
Shareef et al. 3	Case series (12)	2017	Iraq
Yavalkar and Shelke 18	Case report (1)	2014	India

Results

A total of 42 female patients were included in the study. The mean age of the patients was 18.8 years with a standard deviation of 3.3 years. The majority of patients were reported from Turkey (54.7%, n = 23), followed by Iraq (30.9%, n = 13), India (11.9%, n = 5), and the USA (2.4%, n = 1).

BMI data was available for 14 patients, with a mean of 28.74 kg/m² and a standard deviation of 5.132.

A majority of the patients’ comorbidities were not reported; however, one case reported obesity, and eight cases had polycystic ovary syndrome (PCOS). Among the identified risk factors, wearing tight brassieres and having large breasts were reported in the majority of cases. Other risk factors included hypertrichosis, family history of IMPSD, and hyperpigmentation.

Among the study population, only three patients (9.09%) had associated other PNSs, which were only reported at the sacrococcygeal region.

Clinical presentation predominantly involved a discharging sinus (n = 19, 28, 66.66%), followed by painful swelling (n = 12, 36.36%). A recurrent cyst was noted only in one patient (3.03%). The mean duration of symptoms was 8.4 months with a standard deviation of 2.9 months. During examination, multiple tracts were found in 71.42% of cases, while a single tract was found in 28.57% (Table 2).

Table 2.

Clinicopathological characteristics of the study population.

Clinical characteristics	n (%)
Clinical presentation
Discharging sinus	28 (66.66)
Painful swelling	12 (28.57)
Referred after multiple drainages	1 (3.03)
Recurrent cyst	1 (2.38)
Duration of symptoms
8.4 ± 2.9
Examination findings
Multiple tracts	14 (87.50)
Single track	2 (12.50)

Investigations to confirm the diagnosis of IMPSD were infrequently performed in the studies. An ultrasound scan of the breast was performed in two cases and a magnetic resonance imaging (MRI) breast in one case. Treatment options primarily included excision with primary closure (n = 38, 90.5%), followed by resection with secondary healing (n = 3, 7.14%) and curettage (n = 1, 2.38%). Histopathological examination confirmed the diagnosis post-surgery in 15 cases, with acute inflammation observed in majority, followed by chronic inflammation. The average follow-up duration was 7.1 months with a standard deviation of 7.6 months. Recurrence of the condition was noted in three cases (7.14%).

Discussion

This scoping review was conducted to map and characterize the existing literature on IMPSD. Only 11 studies were available in the literature, which included only case reports and case series, reflecting the uncommon nature of this condition.

Clinical characteristics

Our study population consisted of females and was predominantly affecting the young population, typically those under 21 years of age. This parallels the demographic distribution of PNS in other regions. However, other PNS disease is frequently diagnosed in young males (four times more often than females) and mostly in the second and third decades of life. ¹⁹

When considering the geographical distribution, the majority of cases were reported from Turkey, India, and Iraq, indicating potential geographical and genetic predispositions. Mean BMI was 28.74 kg/m², indicating the association of IMPSD with being overweight. Obesity is a known risk factor for PNS. ⁷ However, in our study, only one patient with intermammary PNS was obese.

In addition, the presence of comorbidities such as PCOS was present in 24% of the cases. A study on hirsutism in PCOS reported that the prevalence of hirsutism ranges from 70% to 80% compared to the general population which ranges from 4% to 11%. ¹⁹ As hirsutism is a risk factor for IMPSD, it can be postulated that there is an association between PCOS and IMPSD.

The other risk factors identified for the development of IMPSD included wearing tight brassieres and having large breasts, a family history of IMPSD, and hyperpigmentation. ³ These risk factors align with those identified for sacrococcygeal PNSs such as hairiness, obesity, personal hygiene, sedentary lifestyle, and positive family history.^19,20

Clinical presentation and diagnosis

The majority of IMPSD presented with a discharging sinus (66.66%) and painful swelling (28.57%). This is similar to the clinical presentation of other PNS, which present as an acute abscess or a discharging sinus. ¹⁰ The mean duration of symptoms was 8.4 months, indicating the chronic nature of the condition.

Complementary investigations for the diagnosis of IMPSD are seldom needed, as the diagnosis is usually clinical. ⁹ Therefore, investigations for the diagnosis of IMPSD were performed infrequently with ultrasound and MRI in only a few cases. The USS breast reports showed cystic masses with dense particulate material in the subcutaneous tissue and the MRI breast showed a lesion measuring approximately 2cm with hyperintensity in T2A and hypointensity in T1A sequence. ⁴ This demonstrates that limited additional information can be gathered from complementary investigations and that IMPSD can be reliably diagnosed by clinical assessment. However, Imaging may be helpful in complex cases to guide surgical management.

Treatment and outcomes

The preferred treatment of pilonidal cysts is still debated, with both conservative and surgical techniques being discussed. ²¹ The primary treatment modality for IMPSD was surgical excision, with primary closure performed in the majority of cases (n = 29). Resection with secondary healing (n = 3) and curettage (n = 1) were the other treatment modalities. The majority of the patients had multiple pits that may have warranted wider excision and bigger scars in the intermammary region. Özkan et al. describes a flap method based on primary closure similar to the Karydakis flap used in the sacrococcygeal region. ¹² He reports no complications and no recurrence with his technique. However, none of the studies reported on scarring, aesthetic outcome, and quality of life of the patient’s following treatment.

In our study, the recurrence rate reported was 7.14% (n = 3). Among these three patients, two patients were treated by excision and direct primary closure, whereas the third patient was treated by excision and secondary healing. ³ A Cochrane review evaluating 26 studies on other PNS compared primary and secondary closure and showed no clear benefit for open healing over surgical closure. ²¹ Our study population is also too low to arrive at any inferences.

None of the studies have described risk factors for recurrence. However, literature on other PNS show that factors contributing to recurrence include BMI, family history, bathing habits, hair overgrowth, skin color and oiliness, time spent sitting per day, smoking habits, presence of abscess, and symptom duration. ²² These factors show that measures could be taken to reduce recurrence rates by modifying preventable factors.

The mean follow-up duration was 7.1 months, highlighting that a longer duration of follow-up is necessary to assess the risk of recurrence and long-term outcomes. Histopathological examination was performed only in some cases to confirm the diagnosis.

Management challenges

IMPSD poses several challenges in the management, especially due to its anatomical location and cosmetic concerns associated with surgery and scarring of the intermammary region. It is further complicated by the young age of the affected individuals. None of the studies assessed the QoL and aesthetic outcome following surgery in the intermammary region, which is an important aspect considering the young population affected.

Limitations

A limitation of the scoping review was that only 42 patients from 11 articles were included in the study, exhibiting the limited literature on IMPSD. There were limitations in the studies selected for the scoping review as they were primarily case reports and case series, which have limitations such as a lack of control groups. Therefore, it would be beneficial to address the limitations in future research through prospective studies to provide more evidence for the management of IMPSD.

Conclusions and recommendations

This scoping review highlights the necessity for prospective research on the management of IMPSD, especially to evaluate the best surgical option with minimum scarring and to improve the quality of life of affected individuals.

We recommend that it is important to formulate an individualized plan for the patient, based on a comprehensive evaluation of clinicopathological characteristics and the patient’s wishes.

Supplemental Material

sj-docx-1-whe-10.1177_17455057251351739 – Supplemental material for A scoping review on clinicopathological characteristics, diagnosis, and management of intermammary pilonidal sinus disease

Supplemental material, sj-docx-1-whe-10.1177_17455057251351739 for A scoping review on clinicopathological characteristics, diagnosis, and management of intermammary pilonidal sinus disease by Sepalika Wijekoon, Hasthaka Dissanayake, Umayanga Dehigama, Jeewantha Senevirathna, Hasangi Gamage, N. P. M. Surage, G. K. P. M. Godakanda and Kanchana Wijesinghe in Women’s Health